gwt-openlayers-users — Users list. Moderately active.

[Gwt-openlayers-users] Vector + StyledMap example

[ricky c. <clo...@gm...>]

Hi there,

are there gwt-openlayer examples on using Vector + StyledMap? Sort of
like the styled vectors in
http://openlayers.org/dev/examples/ordering.html

i am using Markers to represent icons at the moment (and where needed,
overriding icon's draw method to display labels), however the OL
documentation seem to suggest markers should be replaced by Vectors
(http://docs.openlayers.org/library/overlays.html), so I'm wondering
if anyone knows how to do that in GWT-Openlayers? Thanks

regards,
Ricky

[Gwt-openlayers-users] MapMoveEndListener contribution

[ricky c. <clo...@gm...>]

hi there,

I implemented something to get the moveend event from openlayers when
the map has stopped moving (from drag etc), posting here for
review/addition to code base if deemed fit.
here's what i did:

1) add moveend to EventType:
        public static final String MAP_MOVE_END = "moveend";

2) create a move end listener and event:
public interface MapMoveEndListener extends EventListener {

    class MapMoveEndEvent extends MapEvent {
        public MapMoveEndEvent(EventObject eventObject) {
            super(eventObject.getJSObject());
        }
    }

    void onMapMoveEnd(MapMoveEndEvent eventObject);
}

3) then a method on map to allow addition of move end listener:
    public void addMapMoveEndListener(final MapMoveEndListener listener) {
        eventListeners.addListener(this, listener,
EventType.MAP_MOVE_END, new EventHandler() {
            public void onHandle(EventObject eventObject) {
                MapMoveEndListener.MapMoveEndEvent e = new
MapMoveEndListener.MapMoveEndEvent(eventObject);
                listener.onMapMoveEnd(e);
            }
        });
    };

regards,
Ricky

Re: [Gwt-openlayers-users] beginner question: TMS custom url

[Edwin C. <com...@gm...>]

Hi Ricky,

If getURL is not a parameter on TMSOptions and you do need it, then
you could try to do it like this:

TMSOptions options = new TMSOptions();
...
options.getJSObject().setProperty("getURL", "yourURL"); //the way to
set properties if there is not yet a setter method

or subclass TMSOptions yourself and create a setter for getURL.

If it works, I would be most happy to incorporate any enhancements to
TMS in the GWT-OL codebase.

Greetings,
Edwin

P.S. I am not a TMS user but, in the example provided at the url below
(tilepyramider stuff) the getURL is not specified:
http://code.google.com/p/cumberland/wiki/TilePyramiderAndOpenLayers


2009/10/6 ricky chen <clo...@gm...>:
> Hi Edwin,
>
> thank you very much for your reply.
>
> I am not familiar with OpenLayers in general (but am looking to use it
> in place of google maps). I'll do my best to explain, please bear with
> me:
>
> in javascript, i have an example (the generated openlayers html from
> maptiler http://www.maptiler.org/) defining custom layer as
> <code>
> var tmsoverlay = new OpenLayers.Layer.TMS( "TMS Overlay", "",
>  {serviceVersion: '.', layername: '.', alpha: true,
>   type: 'png', getURL: overlay_getTileURL,
>   isBaseLayer: false});
> map.addLayer(tmsoverlay);
> </code>
>
> notice how one of the parameters passed in is "getURL: overlay_getTileURL"?
> that is actually a function defining how tile URLs are worked out
> <code>
> function overlay_getTileURL(bounds) {
>  bounds = this.adjustBounds(bounds);
>  var res = this.map.getResolution();
>  var x = Math.round((bounds.left - this.tileOrigin.lon) / (res *
> this.tileSize.w));
>  var y = Math.round((bounds.bottom - this.tileOrigin.lat) / (res *
> this.tileSize.h));
>  var z = this.map.getZoom();
>  var path = this.serviceVersion + "/" + this.layername + "/" + z +
> "/" + x + "/" + y + "." + this.type;
>  var url = this.url;
>  if (mapBounds.intersectsBounds( bounds ) && z >= mapMinZoom && z <=
> mapMaxZoom){
>    // console.log( this.url + z + "/" + x + "/" + y + "." + this.type);
>    out.write(this.url + z + "/" + x + "/" + y + "." + this.type);
>    return this.url + z + "/" + x + "/" + y + "." + this.type;
>  } else {
>    return "http://www.maptiler.org/img/none.png";
>  }
> }
> </code>
>
> so i was looking for some way to provide this tile URL logic when
> experimenting with gwt-openlayers. I can see it takes an URL before
> the TMSOption argument (as you've pointed out) but i'm not sure how
> that URL is resolved for individual tiles?
>
> thanks,
> ricky
>
> On 10/5/09, Edwin Commandeur <com...@gm...> wrote:
>> Hi Ricky,
>>
>> I am not sure I understand the question fully ( I don't work with TMS
>> layers myself ), but as far as I can see the url needs to be specified
>> in the constructor of the TMS layer as a seperate argument (before the
>> TMSOptions argument)
>>
>> Greetings,
>> Edwin
>>
>> 2009/10/5 ricky chen <clo...@gm...>:
>>> hi there,
>>>
>>> I have a question about defining custom URL when adding a TMS layer to
>>> the map (I am emailing you guys as instructed by
>>> http://sourceforge.net/projects/gwt-openlayers/support)
>>>
>>> when I look at general openlayers tutorial that work with custom
>>> overlays, they do so by specifying an URL for getting tiles within
>>> TMSOptions (a function that maps lat/lng to URL of tile), however I
>>> don't see an equivalent in java class - there is TMSOptions but I'm
>>> not sure how to provide a custom URL for different lat/lng.
>>>
>>> Are custom URLs for TMS supported by GWT Openlayers?
>>> Thanks heaps,
>>> Ricky
>>>
>>
>

Re: [Gwt-openlayers-users] Adding Map Event Handlers ...

[Edwin C. <com...@gm...>]

Hi Ken,

Let me know if it works. You can look at the EventHandlerImpl to see
how the onHandle method of EventHandler is called from javascript.
EventHandler and the code using it is documented with JavaDoc, so that
may be a good place to look how the abstract class trick works.

I would say that in the click handler case empty methods vs abstract
methods would be best, because with abstract methods someone who
provides an anonymous implementation would need to implement all
abstract methods.

Very kind that you consider contributing back your efforts.

Greetings and good luck,
Edwin

2009/10/5 Ken Needham <ke...@ke...>:
> OK, I'll give that a go
> Assuming it all works I'll submit the changes for inclusion
> Might as well try to do it properly I suppose.
> Ken
>
>
>
>

Re: [Gwt-openlayers-users] Adding Map Event Handlers ...

[Ken N. <ke...@ke...>]

OK, I'll give that a goAssuming it all works I'll submit the changes for
inclusion
Might as well try to do it properly I suppose.

Ken

Re: [Gwt-openlayers-users] beginner question: TMS custom url

[Edwin C. <com...@gm...>]

Hi Ricky,

I am not sure I understand the question fully ( I don't work with TMS
layers myself ), but as far as I can see the url needs to be specified
in the constructor of the TMS layer as a seperate argument (before the
TMSOptions argument)

Greetings,
Edwin

2009/10/5 ricky chen <clo...@gm...>:
> hi there,
>
> I have a question about defining custom URL when adding a TMS layer to
> the map (I am emailing you guys as instructed by
> http://sourceforge.net/projects/gwt-openlayers/support)
>
> when I look at general openlayers tutorial that work with custom
> overlays, they do so by specifying an URL for getting tiles within
> TMSOptions (a function that maps lat/lng to URL of tile), however I
> don't see an equivalent in java class - there is TMSOptions but I'm
> not sure how to provide a custom URL for different lat/lng.
>
> Are custom URLs for TMS supported by GWT Openlayers?
> Thanks heaps,
> Ricky
>

Re: [Gwt-openlayers-users] Adding Map Event Handlers ...

[Edwin C. <com...@gm...>]

Hi Ken,

It sounds reasonable that you want to keep all non standard stuff separate.

If you would like to contribute a click handler that would be very
welcome. From your code it seems a click control is not even
necessary.

The click handler should be an abstract class with empty callback
functions, that can be overridden in an anonymous instance of the
click handler. For example:

abstract class ClickHandler extends JSObjectWrapper(){

//override
public void onClick(ClickEventObject obj){};

}

Then it needs to be instantiated like:

new ClickHandler(){

  public void onClick(){
    //do sth here
  }
}

The javascript code would have to make a new javascript click handler
that calls the empty callback methods on the abstract java click
handler.

That would be the first solution that would come to mind.

If you would like to contribute a click handler or other such
solution, then you would be more than welcome. I will not have time to
work on it in the very near future.

Greetings,
Edwin


2009/10/5 Ken Needham <ke...@ke...>
> I have numerous changes to make to a (rather over complicated) GIS
> application
> The policy has been to leave the GWT-OpenLayers code untouched and to create
> yet another layer on top in which we handle all the non-standard stuff.
> In this case do you think I would be useful for me to add a new handler into
> the GWT-OpenLayer code?
>
> The pure OL JavaScript approach is as follows:
>
> <html>
>   <head>
>     <script type="text/javascript"
> src="http://openlayers.org/api/OpenLayers.js"></script>
>   </head>
>   <body onload="loadmap();">
>     <script type="text/javascript">
>
> function centre(evt, map){
>         var newCenter = map.getLonLatFromViewPortPx( evt.xy );
>         map.setCenter(newCenter);
> }
>       function loadmap(){
>         //basic setup
>         var map = new OpenLayers.Map('map');
>         var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS",
> "http://labs.metacarta.com/wms/vmap0", {layers: 'basic'} );
>         map.addLayer(wms);
>         if (!map.getCenter()) map.zoomToMaxExtent();
>
>         //Create handler
>         var dblclick = new OpenLayers.Handler.Click(this, {
>        dblclick:function(evt) { centre(evt, map); } },
>        {'double': true,
>        stopDouble: true});
>
>         //Fix up the missing map reference
>         dblclick.setMap(map);
>
>         //Activate in correct order
>         dblclick.activate();
>       }
>     </script>
>
>    <div style="width:1000px; height:500px; border: 1px blue solid;"
> id="map"></div>
>     <div id="eventlog"></div>
>   </body>
> </html>
>
> Ken
>
>
>
>
> ------------------------------------------------------------------------------
> Come build with us! The BlackBerry&reg; Developer Conference in SF, CA
> is the only developer event you need to attend this year. Jumpstart your
> developing skills, take BlackBerry mobile applications to market and stay
> ahead of the curve. Join us from November 9&#45;12, 2009. Register now&#33;
> http://p.sf.net/sfu/devconf
> _______________________________________________
> Gwt-openlayers-users mailing list
> Gwt...@li...
> https://lists.sourceforge.net/lists/listinfo/gwt-openlayers-users
>
>

Re: [Gwt-openlayers-users] Adding Map Event Handlers ...

[Ken N. <ke...@ke...>]

I have numerous changes to make to a (rather over complicated) GIS
application
The policy has been to leave the GWT-OpenLayers code untouched and to create
yet another layer on top in which we handle all the non-standard stuff.
In this case do you think I would be useful for me to add a new handler into
the GWT-OpenLayer code?


The pure OL JavaScript approach is as follows:

<html>  <head>
    <script type="text/javascript" src="
http://openlayers.org/api/OpenLayers.js"></script>
  </head>
  <body onload="loadmap();">
    <script type="text/javascript">

function centre(evt, map){
        var newCenter = map.getLonLatFromViewPortPx( evt.xy );
        map.setCenter(newCenter);
}
       function loadmap(){
        //basic setup
        var map = new OpenLayers.Map('map');
        var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS", "
http://labs.metacarta.com/wms/vmap0", {layers: 'basic'} );
        map.addLayer(wms);
        if (!map.getCenter()) map.zoomToMaxExtent();

        //Create handler
        var dblclick = new OpenLayers.Handler.Click(this, {
       dblclick:function(evt) { centre(evt, map); } },
       {'double': true,
       stopDouble: true});

        //Fix up the missing map reference
        dblclick.setMap(map);

        //Activate in correct order
        dblclick.activate();
      }
    </script>

   <div style="width:1000px; height:500px; border: 1px blue solid;"
id="map"></div>
    <div id="eventlog"></div>
  </body>
</html>


Ken

Re: [Gwt-openlayers-users] Adding Map Event Handlers ...

[Edwin C. <com...@gm...>]

Hi Ken,

I doesn't seem your missing the obvious. I guess the best way is to
start from the OL clickhandler example. GWT-OL is missing a click
control (which also isn't formally in OL, but would be convenient in
GWT-OL) and it is also missing a wrapper for the clickhandler.

How would you do it in pure javascript?

Greetings,
Edwin

2009/10/2 Ken Needham <ke...@ke...>:
> Just started using GWT-OpenLayers so I may be missing the obvious here.
> I need to implement a new handler for the map double click event (we just
> want to centre on the click location rather than zoom to it as is the
> default)
> I can do it easily enough in pure javascript openlayers
> But now I need to do it via gwt-openlayers
> I've got as far as the addMapClickListener code but this only allows me to
> handle a single click, as far as I can see
> I know not all addXxxListener methods have not been implemented so what is
> the best way for me to add the double click handler?
> Any sort of nudge in the general direction would be much appreciated
> Ken Needham
> ------------------------------------------------------------------------------
> Come build with us! The BlackBerry&reg; Developer Conference in SF, CA
> is the only developer event you need to attend this year. Jumpstart your
> developing skills, take BlackBerry mobile applications to market and stay
> ahead of the curve. Join us from November 9&#45;12, 2009. Register now&#33;
> http://p.sf.net/sfu/devconf
> _______________________________________________
> Gwt-openlayers-users mailing list
> Gwt...@li...
> https://lists.sourceforge.net/lists/listinfo/gwt-openlayers-users
>
>

[Gwt-openlayers-users] Adding Map Event Handlers ...

[Ken N. <ke...@ke...>]

Just started using GWT-OpenLayers so I may be missing the obvious here.
I need to implement a new handler for the map double click event (we just
want to centre on the click location rather than zoom to it as is the
default)
I can do it easily enough in pure javascript openlayers
But now I need to do it via gwt-openlayers

I've got as far as the addMapClickListener code but this only allows me to
handle a single click, as far as I can see
I know not all addXxxListener methods have not been implemented so what is
the best way for me to add the double click handler?

Any sort of nudge in the general direction would be much appreciated

Ken Needham

Re: [Gwt-openlayers-users] Coordination of development?

[Edwin C. <com...@gm...>]

Hi Tuure,

There is a developer mailing list that is only visible to developers
and there is Trac.

I must say that both are still not used intensively. The activity is
still moderate, but if you like to help improve that you are more than
welcome. You can anonymously submit tickets to Trac, so that is also a
way to help out, because the tickets can serve to make up a roadmap
when attached to milestones.

If you have patches you can send them to me. I will have a look and
get them in if they are ok. If you are planning to contribute more,
than I would be happy to add you as developer. Since I am short on
time I also do not have the time to setup a very formal track to get
into the developer team.

Greetings,
Edwin

2009/9/29 Tuure Laurinolli <tuu...@in...>:
> Hello,
>
> I have tested gwt-openlayers in some recent projects. So far it has
> worked well, but access to some OpenLayers features is missing.
>
> It seems that there is some development going on (last commits to hg
> were about a week ago), but I don't see any developer-centric
> communication channel mentioned anywhere and this mailing list seems
> awfully quiet. How do the developers communicate? On the whole, how do I
> get my patches in?
>
>
> ------------------------------------------------------------------------------
> Come build with us! The BlackBerry&reg; Developer Conference in SF, CA
> is the only developer event you need to attend this year. Jumpstart your
> developing skills, take BlackBerry mobile applications to market and stay
> ahead of the curve. Join us from November 9&#45;12, 2009. Register now&#33;
> http://p.sf.net/sfu/devconf
> _______________________________________________
> Gwt-openlayers-users mailing list
> Gwt...@li...
> https://lists.sourceforge.net/lists/listinfo/gwt-openlayers-users
>

[Gwt-openlayers-users] Coordination of development?

[Tuure L. <tuu...@in...>]

Hello,

I have tested gwt-openlayers in some recent projects. So far it has 
worked well, but access to some OpenLayers features is missing.

It seems that there is some development going on (last commits to hg 
were about a week ago), but I don't see any developer-centric 
communication channel mentioned anywhere and this mailing list seems 
awfully quiet. How do the developers communicate? On the whole, how do I 
get my patches in?

[Gwt-openlayers-users] Building from source to add RegularPolygon

[Roland S. <Rol...@no...>]

Hi,

I'm so glad to see this project getting some traction.  I'm interested 
in adding the RegularPolygon handler so I've grabbed the source.  It 
seems to be missing these classes:

org.gwtopenmaps.openlayers.client.handler.HandlerOptions
org.gwtopenmaps.openlayers.client.event.MeasureEvent
org.gwtopenmaps.openlayers.client.event.MeasureListener
org.gwtopenmaps.openlayers.client.event.MeasurePartialListener

I thought I might be able to create some stubs and get going, but I 
eventually ran aground.

Any chance these are available in somebody's working copy and could be 
added to the repository?  Or did I miss something along the way?  I'm 
new to Mercurial...

Looking forward to contributing a RegularPolygonHandler...

Thanks,
Roland

Re: [Gwt-openlayers-users] WFS Params

[Philipp H. <phi...@pa...>]

Hi!

actually i am having the same problem as well. i figure there are 
classes for WFSParams and WFSOptions, but it is not possible to 
instantiate WFSParams because there is no publically available constructur.

Am i missing something? I'm using gwt-openlayers 0.4.

thanks
Philipp

[Gwt-openlayers-users] How to display features that are stored in PostGIS

[www.gwtorm.com <jim...@gm...>]

I have data stored in POSTGIS. I can access them through GWT-RPC. What is
best way to retrieve them from POSTGIS and display them on a map in
performance.
1. as double[][]
2. KML
3. GML
4. GeoJSON.
...

I tested KML as in the following code. It doesn't display anything on a map.

                    KML kml = new KML();
                    VectorFeature[] features = kml.read(json);
                    System.out.println(features.length);
//                  VectorFeature vectorFeature = new VectorFeature();
//
                    VectorOptions vectorOptions = new VectorOptions();
                    vectorOptions.setVisibility(true);

                    vector = new Vector("GeoJSON", vectorOptions);
                    vector.addFeatures(features);

                   map.addLayer(vector);

json is a KML string returned from GWT-RPC. I tested the same KML on
http://kml-samples.googlecode.com/svn/trunk/interactive/index.html#./Multi-Geometries/Multi-Geometries.Simple.kml.
It works perfectly.


Thanks,

Jim

Re: [Gwt-openlayers-users] WFS Params

[Edwin C. <com...@gm...>]

Hi AbdelHadi,

Have you looked at the WMSParams vs WMSOptions.

It should be the same for WFS. You can pass it as a parameter to the WFS
constructor.

You do know that you will likely need a proxy for WFS? Or is the OpenLayers
proxy sufficient for you?

Greetings,
Edwin

2009/8/26 AbdElhadi <abd...@gm...>

> Hi Edwin,
>
> I am unable to construct a WFSParams object which is necessary to create a
> WFS Layer. How do you get around that?
>
> Thanks,
> --
> Abdelhadi
>

[Gwt-openlayers-users] WFS Params

[AbdElhadi <abd...@gm...>]

Hi Edwin,

I am unable to construct a WFSParams object which is necessary to create a
WFS Layer. How do you get around that?

Thanks,
-- 
Abdelhadi

[Gwt-openlayers-users] GWT-OL OpenLayersObjectWrapper

[Edwin C. <com...@gm...>]

Hi Michel,

What exactly are the doubts you have about OpenLayersObjectWrapper?

It extends JSObjectWrapper and wraps JSObject. JSObject is a class that adds
some functionality to JavaScriptObject. JavaScriptObject is the handle GWT
provides on Javascript objects (makes sense :-)....). For a deeper
understanding of JavaScriptObject and interacting with Javascript from GWT,
I would have to refer you to the GWT documentation. JSObject and other
classes from util help dealing with the Javascript/Java communication.

There are two ways to "wrap" a Javascript object:
a) provide a wrapper class that holds on to the Javascript object via the
handles GWT provides (in our case JSObject)
b) extend JavaScriptObject/JSObject directly, which GWT calls Overlay types

In GWT we have choosen for the first option. The only difference is that in
option (a) you do getJSObject() to get at the handle on the Javascript
object you are wrapping, while in option (b) you can access the handle on
your Javascript object via this.

Overlay types were not available when GWT-OL was created and I have a slight
favor for the explicit wrapping, as it makes it more clear that you are
"wrapping" something. It is a case of favoring Composition over Inheritance.
Also, then we do not need to do anything to hide methods defined on JSObject
to users.

OpenLayersObjectWrapper simply defines methods/properties that every
OpenLayers object will have, so these can be share by all classes wrapping
OpenLayers objects. Currently I it only has getClassName() and getEvents().
The latter is defined there because you also might want to test if a class
has an Events object (and fires events).

If you are wrapping a Javascript object and it is an OpenLayers object, then
you should extend OpenLayersObjectWrapper. If it is an OpenLayers object
that fires event, then you should extend OpenLayersEObjectWrapper. Otherwise,
you shouldn't extend OpenLayers(E)ObjectWrapper

StyleMap is an OpenLayers object so it would extend OpenLayersObjectWrapper.

If you do:
var sm = new OpenLayers.StyleMap();

Then you get an object with a CLASS_NAME. That is why it should be wrapped
by OpenLayersObjectWrapper.

Greetings,
Edwin





2009/8/21 Michel vitor <mic...@gm...>

> Dear Edwin,
>
> I'm trying to make a function in Measure OL  but I have a doubt about the
> class OpenLayersObjectWrapper and
> you could give me a description of their functionality
> because I need to create a class StyleMap.js.
>
> --
> Michel Vitor A Rodrigues
> 6° Periodo de Computação
> Grupo Intec,Viçosa MG
>
>

Re: [Gwt-openlayers-users] Change GWT-OL

[Edwin C. <com...@gm...>]

Hi Michel,

I had a look at the Google Maps API and they also have a getIcon() method on
GMarker (and no setIcon, which seems logical as you want to change
properties on the icon rather than make a whole new icon).

Additionally Googe Maps API has a setImage(String url) method, which in
OpenLayers corresponds to setUrl(String url). We can wrap the setUrl method
with a bit more descriptive name in GWT-OL like setImageUrl(String url).

Greetings,
Edwin

2009/8/19 Michel vitor <mic...@gm...>

> Dear Edwin,
>
> I am sending you an attachment with the two classes that also the modified
> form's javascript file Openlayers with the two new functions.
> As they leave that changed the sources did it for personal use.
> If you have any suggestions on how to do this in anything but I am
> available.
>
> --
> Michel Vitor A Rodrigues
> 6° Periodo de Computação
> Grupo Intec,Viçosa MG
>
>

Re: [Gwt-openlayers-users] EPSG: 900913 Vs 3785

[AbdElhadi <abd...@gm...>]

UPDATE:

Apparently, openlayers uses whichever EPSG used by the base layer for all
the WMS layers added on top of it. Since my baselayer is a Google Map, it is
using 900913 for all subsequent wms requests. My WMS supports 3785 only.

Is there a way to set a baselayer with a projection different from the other
layers? Has anybody gotten around this?

Thanks!

On Tue, Aug 11, 2009 at 4:11 PM, AbdElhadi <abd...@gm...>wrote:

> Hi Edwin,
>
> Whenever I try to use the 3785 srs instead of the deprecated 900913, it
> gets converted to the latter causing my WMS server, which supports only
> EPSG:3785,  to issue an error. Is there a switch setting I can set to false
> to make this behavior disappear?
>
> Thanks!
>
> --
> Abdelhadi
>



-- 
Abdelhadi

[Gwt-openlayers-users] EPSG: 900913 Vs 3785

[AbdElhadi <abd...@gm...>]

Hi Edwin,

Whenever I try to use the 3785 srs instead of the deprecated 900913, it gets
converted to the latter causing my WMS server, which supports only
EPSG:3785,  to issue an error. Is there a switch setting I can set to false
to make this behavior disappear?

Thanks!

-- 
Abdelhadi

Re: [Gwt-openlayers-users] Fwd: WFS Operations

[Edwin C. <com...@gm...>]

Hi AbdElhadi,

That is indeed a good suggestion to pre-generate the SLD's. By far the
easiest if it is sufficient.

A colleague of mine worked on the proxy, he is an experienced Java
programmer. I will ask him how long it took (I guess between one and two
weeks to get a working proxy). Most of the time went into finding out how to
generate SLD's dynamically and that kind of stuff. We do indeed style the
map based on for example user selections. We do that via SLD/WMS, because we
have pretty complex geometries to deal with and drawing the selection client
side is not an option.

Greetings,
Edwin

2009/8/10 AbdElhadi <abd...@gm...>

> Edwin,
>
> How much effort did it take you/your company to make the proxy? It is a
> very attractive idea to let the WMS server deal with styles and colors and
> let your code only deal with the rules.
>
> Also, and this for Cameron, you might not need going through building a
> proxy yourself. If the number of map scenarios is limited, you can
> pre-generate the SLDs and manage the logic that chooses which one to use in
> your code. The time you might save could be substantial. You only need a
> proxy if you don't know beforehand what kind of theme the user is going to
> try to create, like in a web app that allows the user to change the colors
> and the thresholds used for theming dynamically in the UI and be able to see
> the results right away.
>
> Cheers,
>
>
> On Sun, Aug 9, 2009 at 10:08 PM, Edwin Commandeur <
> com...@gm...> wrote:
>
>> Hi Cameron,
>>
>> First, a correction. I checked and the WFS class  was already in
>> OpenLayers 2.7 and OL versions before that. Although it is true that there
>> were many enhancements relating to WFS in OpenLayers 2.8.
>>
>> Anyway, I remember why it is relevant to know about the proxy. For
>> instance, I work on Windows, and the proxy is a python script that is set up
>> to run under Linux. The problem is: when the proxy doesn't work, the WFS
>> stuff doesn't work.
>>
>> You need a proxy to do WFS requests, because of cross-domain restrictions
>> on Ajax requests. There are solutions for doing cross-domain GET requests,
>> but doing cross-domain POST requests can only work with a proxy as far as I
>> know.
>>
>> Furthermore, the proxy that comes with OpenLayers is not very
>> sophisticated and may even present a security risk when it is accessible
>> outside your app. See also the comments in the proxy.cgi file.
>>
>> For GWT-OL it makes sense to have a proxy servlet in java. I may need to
>> look into that. Preferably, I want to keep GWT-OL client-side. Maybe, it is
>> necessary to start a "GWT-OL server" project that provides server side
>> components, such as a WFS proxy and a print servlet.
>>
>> Due to the cross-browser restrictions issue I had not looked deeply into
>> the WFS.
>>
>> Now onto what you describe. If you want to shade the map based on what
>> software version clients are using then you need SLD's. You probably want to
>> proxy the WMS call that OpenLayers does, and let the proxy do a WMS call
>> with an SLD that shades the map based on the version of the software. This
>> is not trivial unfortunetaly. We are using GeoTools for the SLD building in
>> a custom proxy that is proprietary.
>>
>> Why would you want to manually loop through polygons on the map? If for
>> instance the polygons are the states of the USA and they all have a property
>> CAPITAL, then you would want to store the polygons in a spatially enabled
>> database (PostGis or Oracle Spatial are the most common ones). A WMS server
>> could draw a map from those polygons. When someone clicks the map you either
>> do a getFeatureInfo request on the WMS to get the property, or you pass the
>> coordinate to the database and let a spatial query sort out in which polygon
>> the coordinate falls.
>>
>> I am not reading any use cases for WFS in your mail. WFS is also a bit
>> tricky, because you can kill the browser if the geometries of your features
>> are complicated, or if you have to draw a lot of features (that is really a
>> lot). I have seen that happen, that a getFeature request returns several mb
>> of reponse, killing the browser.
>>
>> As an aside, you can also draw your own geometries on the map in a Vector
>> layer.
>>
>> Greetings,
>> Edwin Commandeur
>>
>> P.S. In case you are wondering: With WMS it is possible to overcome cross
>> browser restrictions by using the image tag in WMS layers. The src attribute
>> of the image tag can point at any url.
>>
>> P.S. P.S. GWT and GWT-OL let you abstract from javascript and html, but
>> that doesn't mean you don't have to learn javascript and html (or other
>> browser related technologies). GWT solves many issues, such as using plain
>> java OO versus a javascript framework specific type of OO, compressing and
>> optimizing your javascript, make it possible to create modules etc. But
>> eventually, the code runs in the browser and it helps to know about browser
>> specific technologies. Especially CSS, but also javascript and html.
>>
>>
>> ---------- Forwarded message ----------
>> From: Cameron Hunt <CH...@ci...>
>> Date: 2009/8/10
>> Subject: RE: WFS Operations
>> To: Edwin Commandeur <com...@gm...>
>>
>>
>>  Thanks Edwin,
>>
>>
>>
>> I’m happy to beta test anything you want. Just to give you some background
>> we are just in the early stages of an in house web application to track and
>> present customer information via a map. We are actually very new to web
>> development and also Java. We’ve come from a background of Delphi and used
>> TatukGIS VCL component in our old app which was especially easy to use but
>> now we are entering a different world.
>>
>>
>>
>> We would like to do things like shade the map based on what release of our
>> software customers are on. Also accessing external database information via
>> a common field (even if this is just manually retrieving from the DB once we
>> identify the associated polygon on the map). In fact all of our info will be
>> stored in an external database so rendering the map based on attributes will
>> be attributes coming from the DB so I’m hoping to be able to do things like
>> manually loop through the map polygons etc.
>>
>>
>>
>> GWT-OL certainly looks like the easiest way we’ve found so far without
>> having learn Javascript and HTML as well.
>>
>>
>>
>> I’m still coming to terms with understanding WMS and WFS so please forgive
>> me if I ask any dumb questions.
>>
>>
>>
>> So when your new changes come through instead of creating a WMS layer I
>> would create a WFS layer?
>>
>>
>>
>> Cameron
>>
>>
>>  ------------------------------
>>
>> *From:* Edwin Commandeur [mailto:com...@gm...]
>> *Sent:* Monday, 10 August 2009 08:59 AM
>> *To:* gwt...@li...
>> *Cc:* Cameron Hunt
>> *Subject:* WFS Operations
>>
>>
>>
>> Hi Cameron,
>>
>> Like the WMSGetFeatureInfo, the WFS support is also new in OpenLayers 2.8.
>>
>> The WFS support is high on my list to get working with GWT-OpenLayers, but
>> currently it is not in GWT-OL. I am just reworking the GWT-OL code and
>> showcase a little bit (removing warnings and deprecated AddClickListener
>> stuff), but after that I think the WMSGetFeatureInfo Control and the WFS
>> layer will be my primary goals. Having good WMS/WFS support is first on the
>> list, and getting a good Google Maps example a good second.
>>
>> Would be nice to have you as beta tester of the WMSGetFeatureInfo and WFS
>> support, when I get to it. I hope so this week.
>>
>> OpenLayers 2.8 does WFS requests via a cgi proxy to get past the
>> cross-domain restrictions. As a user you should not concern yourself with
>> that to much, but for your information...
>>
>> Greetings,
>> Edwin
>>
>> ---------- Forwarded message ----------
>> From: *Cameron Hunt* <CH...@ci...>
>> Date: 2009/8/10
>> Subject: RE: [Gwt-openlayers-users] Some general beginners questions
>> To: Edwin Commandeur <com...@gm...>
>>
>>   Thank you Edwin,
>>
>>
>>
>> I am using Geoserver so I will look into the WFS operations. Should I be
>> able to perform these operations easily enough using GWT-Openlayers?
>>
>>
>>
>> Thanks.
>>
>>
>>
>> Regards
>>
>> Cameron
>>
>>
>>  ------------------------------
>>
>> *From:* Edwin Commandeur [mailto:com...@gm...]
>> *Sent:* Monday, 10 August 2009 07:20 AM
>> *To:* AbdElhadi
>> *Cc:* Cameron Hunt; gwt...@li...
>> *Subject:* Re: [Gwt-openlayers-users] Some general beginners questions
>>
>>
>>
>> Hi Cameron,
>>
>> *GetFeatureInfo*: Abdelhadi is right about the feature info on a WMS. You
>> would need a WMS server that supports GetFeatureInfo. GeoServer supports
>> GetFeatureInfo requests for example, as does MapServer. Be careful: the
>> GetFeatureInfo response has not been standardized by the OGC.
>>
>> Since OpenLayers 2.8, OpenLayers has WMSGetFeatureInfo control that
>> abstracts over several different GetFeatureInfo response formats. I will add
>> support for that control to GWT-OL.
>>
>> *Thematic mapping*: That is something I think you would have to achieve
>> using SLD's (Styled Layer Descriptors). Since SLD's can get quite big, in
>> our company we wrote a proxy for performing GetMap POST requests with custom
>> SLD's. That proxy is closed source however. You will have to roll your own
>> variant.
>>
>> *Printing*: Printing is always a bit problematic in my experience. You
>> will probably want to build a PDF server side with the information on the
>> map. If the map consists only of pictures (WMS layer, Legend graphics) then
>> you can get quite far with some server side code and a PDF generation
>> framework. There is one open source printing solution that I know of, and
>> that is the MapPrintService in the MapFish framework. At the core it is a
>> Java servlet and right now I am guessing it uses some Java PDF generation
>> library. Printing vector features is a little more challenging.
>>
>> A simple solution for printing is to provide a separate page with a clone
>> of the map in you app, and use the browser to print that. In my experience
>> the vector features get printed also, but you have little control over the
>> printing process itself.
>>
>> Greetings,
>> Edwin Commandeur
>>
>> 2009/8/7 AbdElhadi <abd...@gm...>
>>
>> Hi Cameron,
>>
>> I don't think you can get the feature info from a WMS layer unless the WMS
>> Server supports the GetFeatureInfo. a WMS is basically just an image.
>>
>> AS for Thematics, I don't think OL supports that but I am not sure.
>>
>> Cheers,
>> -Abdelhadi
>>
>> On Thu, Aug 6, 2009 at 11:34 PM, Cameron Hunt <CH...@ci...>
>> wrote:
>>
>>   Hi,
>>
>>
>>
>> I’ve just started using GWT-Openlayers and so far it looks great. Having
>> said that I’ve only done a few basic things. I would very much appreciate it
>> if somebody could give me a couple of quick pointers in the right direction
>> for the following tasks please?
>>
>>
>>
>>    - Finding out the information about an object (e.g. polygon) when user
>>    clicks on map (based on shapefile loaded in as WMS layer)
>>    - Thematic mapping (e.g. shading all polygons based on an attribute).
>>    - Printing. How do people provide basic printing to their users?
>>
>>
>>
>> Thank you.
>>
>>
>>
>> Regards,
>>
>> Cameron Hunt
>> Software Developer
>> Civica Solutions Pty Limited
>>
>> Ph: (07) 46393633
>> Fx: (07) 46393632
>> ch...@ci...
>> www.civica.com.au
>>
>>
>>
>> --
>>
>> This email is from Civica Pty Limited and it, together with
>> any attachments, is confidential to the intended recipient(s)
>> and the contents may be legally privileged or contain
>> proprietary and private information. It is intended solely
>> for the person to whom it is addressed. If you are not an
>> intended recipient, you may not review, copy or distribute
>> this email. If received in error, please notify the sender
>> and delete the message from your system immediately. Any
>> views or opinions expressed in this email and any files
>> transmitted with it are those of the author only and may
>> not necessarily reflect the views of Civica and do not create
>> any legally binding rights or obligations whatsoever. Unless
>> otherwise pre-agreed by exchange of hard copy documents
>> signed by duly authorised representatives, contracts may not
>> be concluded on behalf of Civica by email. Please note that
>> neither Civica nor the sender accepts any responsibility for
>> any viruses and it is your responsibility to scan the email
>> and the attachments (if any). All email received and sent by
>> Civica may be monitored to protect the business interests of
>> Civica.
>>
>>
>>
>>
>> ------------------------------------------------------------------------------
>> Let Crystal Reports handle the reporting - Free Crystal Reports 2008
>> 30-Day
>> trial. Simplify your report design, integration and deployment - and focus
>> on
>> what you do best, core application coding. Discover what's new with
>> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
>> _______________________________________________
>> Gwt-openlayers-users mailing list
>> Gwt...@li...
>> https://lists.sourceforge.net/lists/listinfo/gwt-openlayers-users
>>
>>
>>
>>
>> --
>> Abdelhadi
>>
>>
>> ------------------------------------------------------------------------------
>> Let Crystal Reports handle the reporting - Free Crystal Reports 2008
>> 30-Day
>> trial. Simplify your report design, integration and deployment - and focus
>> on
>> what you do best, core application coding. Discover what's new with
>> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
>> _______________________________________________
>> Gwt-openlayers-users mailing list
>> Gwt...@li...
>> https://lists.sourceforge.net/lists/listinfo/gwt-openlayers-users
>>
>>
>>
>> --
>>
>> This email is from Civica Pty Limited and it, together with
>> any attachments, is confidential to the intended recipient(s)
>> and the contents may be legally privileged or contain
>> proprietary and private information. It is intended solely
>> for the person to whom it is addressed. If you are not an
>> intended recipient, you may not review, copy or distribute
>> this email. If received in error, please notify the sender
>> and delete the message from your system immediately. Any
>> views or opinions expressed in this email and any files
>> transmitted with it are those of the author only and may
>> not necessarily reflect the views of Civica and do not create
>> any legally binding rights or obligations whatsoever. Unless
>> otherwise pre-agreed by exchange of hard copy documents
>> signed by duly authorised representatives, contracts may not
>> be concluded on behalf of Civica by email. Please note that
>> neither Civica nor the sender accepts any responsibility for
>> any viruses and it is your responsibility to scan the email
>> and the attachments (if any). All email received and sent by
>> Civica may be monitored to protect the business interests of
>> Civica.
>>
>>
>>
>> --
>>
>> This email is from Civica Pty Limited and it, together with
>> any attachments, is confidential to the intended recipient(s)
>> and the contents may be legally privileged or contain
>> proprietary and private information. It is intended solely
>> for the person to whom it is addressed. If you are not an
>> intended recipient, you may not review, copy or distribute
>> this email. If received in error, please notify the sender
>> and delete the message from your system immediately. Any
>> views or opinions expressed in this email and any files
>> transmitted with it are those of the author only and may
>> not necessarily reflect the views of Civica and do not create
>> any legally binding rights or obligations whatsoever. Unless
>> otherwise pre-agreed by exchange of hard copy documents
>> signed by duly authorised representatives, contracts may not
>> be concluded on behalf of Civica by email. Please note that
>> neither Civica nor the sender accepts any responsibility for
>> any viruses and it is your responsibility to scan the email
>> and the attachments (if any). All email received and sent by
>> Civica may be monitored to protect the business interests of
>> Civica.
>>
>>
>>
>> ------------------------------------------------------------------------------
>> Let Crystal Reports handle the reporting - Free Crystal Reports 2008
>> 30-Day
>> trial. Simplify your report design, integration and deployment - and focus
>> on
>> what you do best, core application coding. Discover what's new with
>> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
>> _______________________________________________
>> Gwt-openlayers-users mailing list
>> Gwt...@li...
>> https://lists.sourceforge.net/lists/listinfo/gwt-openlayers-users
>>
>>
>
>
> --
> Abdelhadi
>

Re: [Gwt-openlayers-users] Fwd: WFS Operations

[AbdElhadi <abd...@gm...>]

Edwin,

How much effort did it take you/your company to make the proxy? It is a very
attractive idea to let the WMS server deal with styles and colors and let
your code only deal with the rules.

Also, and this for Cameron, you might not need going through building a
proxy yourself. If the number of map scenarios is limited, you can
pre-generate the SLDs and manage the logic that chooses which one to use in
your code. The time you might save could be substantial. You only need a
proxy if you don't know beforehand what kind of theme the user is going to
try to create, like in a web app that allows the user to change the colors
and the thresholds used for theming dynamically in the UI and be able to see
the results right away.

Cheers,

On Sun, Aug 9, 2009 at 10:08 PM, Edwin Commandeur <
com...@gm...> wrote:

> Hi Cameron,
>
> First, a correction. I checked and the WFS class  was already in OpenLayers
> 2.7 and OL versions before that. Although it is true that there were many
> enhancements relating to WFS in OpenLayers 2.8.
>
> Anyway, I remember why it is relevant to know about the proxy. For
> instance, I work on Windows, and the proxy is a python script that is set up
> to run under Linux. The problem is: when the proxy doesn't work, the WFS
> stuff doesn't work.
>
> You need a proxy to do WFS requests, because of cross-domain restrictions
> on Ajax requests. There are solutions for doing cross-domain GET requests,
> but doing cross-domain POST requests can only work with a proxy as far as I
> know.
>
> Furthermore, the proxy that comes with OpenLayers is not very sophisticated
> and may even present a security risk when it is accessible outside your app.
> See also the comments in the proxy.cgi file.
>
> For GWT-OL it makes sense to have a proxy servlet in java. I may need to
> look into that. Preferably, I want to keep GWT-OL client-side. Maybe, it is
> necessary to start a "GWT-OL server" project that provides server side
> components, such as a WFS proxy and a print servlet.
>
> Due to the cross-browser restrictions issue I had not looked deeply into
> the WFS.
>
> Now onto what you describe. If you want to shade the map based on what
> software version clients are using then you need SLD's. You probably want to
> proxy the WMS call that OpenLayers does, and let the proxy do a WMS call
> with an SLD that shades the map based on the version of the software. This
> is not trivial unfortunetaly. We are using GeoTools for the SLD building in
> a custom proxy that is proprietary.
>
> Why would you want to manually loop through polygons on the map? If for
> instance the polygons are the states of the USA and they all have a property
> CAPITAL, then you would want to store the polygons in a spatially enabled
> database (PostGis or Oracle Spatial are the most common ones). A WMS server
> could draw a map from those polygons. When someone clicks the map you either
> do a getFeatureInfo request on the WMS to get the property, or you pass the
> coordinate to the database and let a spatial query sort out in which polygon
> the coordinate falls.
>
> I am not reading any use cases for WFS in your mail. WFS is also a bit
> tricky, because you can kill the browser if the geometries of your features
> are complicated, or if you have to draw a lot of features (that is really a
> lot). I have seen that happen, that a getFeature request returns several mb
> of reponse, killing the browser.
>
> As an aside, you can also draw your own geometries on the map in a Vector
> layer.
>
> Greetings,
> Edwin Commandeur
>
> P.S. In case you are wondering: With WMS it is possible to overcome cross
> browser restrictions by using the image tag in WMS layers. The src attribute
> of the image tag can point at any url.
>
> P.S. P.S. GWT and GWT-OL let you abstract from javascript and html, but
> that doesn't mean you don't have to learn javascript and html (or other
> browser related technologies). GWT solves many issues, such as using plain
> java OO versus a javascript framework specific type of OO, compressing and
> optimizing your javascript, make it possible to create modules etc. But
> eventually, the code runs in the browser and it helps to know about browser
> specific technologies. Especially CSS, but also javascript and html.
>
>
> ---------- Forwarded message ----------
> From: Cameron Hunt <CH...@ci...>
> Date: 2009/8/10
> Subject: RE: WFS Operations
> To: Edwin Commandeur <com...@gm...>
>
>
>  Thanks Edwin,
>
>
>
> I’m happy to beta test anything you want. Just to give you some background
> we are just in the early stages of an in house web application to track and
> present customer information via a map. We are actually very new to web
> development and also Java. We’ve come from a background of Delphi and used
> TatukGIS VCL component in our old app which was especially easy to use but
> now we are entering a different world.
>
>
>
> We would like to do things like shade the map based on what release of our
> software customers are on. Also accessing external database information via
> a common field (even if this is just manually retrieving from the DB once we
> identify the associated polygon on the map). In fact all of our info will be
> stored in an external database so rendering the map based on attributes will
> be attributes coming from the DB so I’m hoping to be able to do things like
> manually loop through the map polygons etc.
>
>
>
> GWT-OL certainly looks like the easiest way we’ve found so far without
> having learn Javascript and HTML as well.
>
>
>
> I’m still coming to terms with understanding WMS and WFS so please forgive
> me if I ask any dumb questions.
>
>
>
> So when your new changes come through instead of creating a WMS layer I
> would create a WFS layer?
>
>
>
> Cameron
>
>
>  ------------------------------
>
> *From:* Edwin Commandeur [mailto:com...@gm...]
> *Sent:* Monday, 10 August 2009 08:59 AM
> *To:* gwt...@li...
> *Cc:* Cameron Hunt
> *Subject:* WFS Operations
>
>
>
> Hi Cameron,
>
> Like the WMSGetFeatureInfo, the WFS support is also new in OpenLayers 2.8.
>
> The WFS support is high on my list to get working with GWT-OpenLayers, but
> currently it is not in GWT-OL. I am just reworking the GWT-OL code and
> showcase a little bit (removing warnings and deprecated AddClickListener
> stuff), but after that I think the WMSGetFeatureInfo Control and the WFS
> layer will be my primary goals. Having good WMS/WFS support is first on the
> list, and getting a good Google Maps example a good second.
>
> Would be nice to have you as beta tester of the WMSGetFeatureInfo and WFS
> support, when I get to it. I hope so this week.
>
> OpenLayers 2.8 does WFS requests via a cgi proxy to get past the
> cross-domain restrictions. As a user you should not concern yourself with
> that to much, but for your information...
>
> Greetings,
> Edwin
>
> ---------- Forwarded message ----------
> From: *Cameron Hunt* <CH...@ci...>
> Date: 2009/8/10
> Subject: RE: [Gwt-openlayers-users] Some general beginners questions
> To: Edwin Commandeur <com...@gm...>
>
>   Thank you Edwin,
>
>
>
> I am using Geoserver so I will look into the WFS operations. Should I be
> able to perform these operations easily enough using GWT-Openlayers?
>
>
>
> Thanks.
>
>
>
> Regards
>
> Cameron
>
>
>  ------------------------------
>
> *From:* Edwin Commandeur [mailto:com...@gm...]
> *Sent:* Monday, 10 August 2009 07:20 AM
> *To:* AbdElhadi
> *Cc:* Cameron Hunt; gwt...@li...
> *Subject:* Re: [Gwt-openlayers-users] Some general beginners questions
>
>
>
> Hi Cameron,
>
> *GetFeatureInfo*: Abdelhadi is right about the feature info on a WMS. You
> would need a WMS server that supports GetFeatureInfo. GeoServer supports
> GetFeatureInfo requests for example, as does MapServer. Be careful: the
> GetFeatureInfo response has not been standardized by the OGC.
>
> Since OpenLayers 2.8, OpenLayers has WMSGetFeatureInfo control that
> abstracts over several different GetFeatureInfo response formats. I will add
> support for that control to GWT-OL.
>
> *Thematic mapping*: That is something I think you would have to achieve
> using SLD's (Styled Layer Descriptors). Since SLD's can get quite big, in
> our company we wrote a proxy for performing GetMap POST requests with custom
> SLD's. That proxy is closed source however. You will have to roll your own
> variant.
>
> *Printing*: Printing is always a bit problematic in my experience. You
> will probably want to build a PDF server side with the information on the
> map. If the map consists only of pictures (WMS layer, Legend graphics) then
> you can get quite far with some server side code and a PDF generation
> framework. There is one open source printing solution that I know of, and
> that is the MapPrintService in the MapFish framework. At the core it is a
> Java servlet and right now I am guessing it uses some Java PDF generation
> library. Printing vector features is a little more challenging.
>
> A simple solution for printing is to provide a separate page with a clone
> of the map in you app, and use the browser to print that. In my experience
> the vector features get printed also, but you have little control over the
> printing process itself.
>
> Greetings,
> Edwin Commandeur
>
> 2009/8/7 AbdElhadi <abd...@gm...>
>
> Hi Cameron,
>
> I don't think you can get the feature info from a WMS layer unless the WMS
> Server supports the GetFeatureInfo. a WMS is basically just an image.
>
> AS for Thematics, I don't think OL supports that but I am not sure.
>
> Cheers,
> -Abdelhadi
>
> On Thu, Aug 6, 2009 at 11:34 PM, Cameron Hunt <CH...@ci...> wrote:
>
>   Hi,
>
>
>
> I’ve just started using GWT-Openlayers and so far it looks great. Having
> said that I’ve only done a few basic things. I would very much appreciate it
> if somebody could give me a couple of quick pointers in the right direction
> for the following tasks please?
>
>
>
>    - Finding out the information about an object (e.g. polygon) when user
>    clicks on map (based on shapefile loaded in as WMS layer)
>    - Thematic mapping (e.g. shading all polygons based on an attribute).
>    - Printing. How do people provide basic printing to their users?
>
>
>
> Thank you.
>
>
>
> Regards,
>
> Cameron Hunt
> Software Developer
> Civica Solutions Pty Limited
>
> Ph: (07) 46393633
> Fx: (07) 46393632
> ch...@ci...
> www.civica.com.au
>
>
>
> --
>
> This email is from Civica Pty Limited and it, together with
> any attachments, is confidential to the intended recipient(s)
> and the contents may be legally privileged or contain
> proprietary and private information. It is intended solely
> for the person to whom it is addressed. If you are not an
> intended recipient, you may not review, copy or distribute
> this email. If received in error, please notify the sender
> and delete the message from your system immediately. Any
> views or opinions expressed in this email and any files
> transmitted with it are those of the author only and may
> not necessarily reflect the views of Civica and do not create
> any legally binding rights or obligations whatsoever. Unless
> otherwise pre-agreed by exchange of hard copy documents
> signed by duly authorised representatives, contracts may not
> be concluded on behalf of Civica by email. Please note that
> neither Civica nor the sender accepts any responsibility for
> any viruses and it is your responsibility to scan the email
> and the attachments (if any). All email received and sent by
> Civica may be monitored to protect the business interests of
> Civica.
>
>
>
>
> ------------------------------------------------------------------------------
> Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day
> trial. Simplify your report design, integration and deployment - and focus
> on
> what you do best, core application coding. Discover what's new with
> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
> _______________________________________________
> Gwt-openlayers-users mailing list
> Gwt...@li...
> https://lists.sourceforge.net/lists/listinfo/gwt-openlayers-users
>
>
>
>
> --
> Abdelhadi
>
>
> ------------------------------------------------------------------------------
> Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day
> trial. Simplify your report design, integration and deployment - and focus
> on
> what you do best, core application coding. Discover what's new with
> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
> _______________________________________________
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> Gwt...@li...
> https://lists.sourceforge.net/lists/listinfo/gwt-openlayers-users
>
>
>
> --
>
> This email is from Civica Pty Limited and it, together with
> any attachments, is confidential to the intended recipient(s)
> and the contents may be legally privileged or contain
> proprietary and private information. It is intended solely
> for the person to whom it is addressed. If you are not an
> intended recipient, you may not review, copy or distribute
> this email. If received in error, please notify the sender
> and delete the message from your system immediately. Any
> views or opinions expressed in this email and any files
> transmitted with it are those of the author only and may
> not necessarily reflect the views of Civica and do not create
> any legally binding rights or obligations whatsoever. Unless
> otherwise pre-agreed by exchange of hard copy documents
> signed by duly authorised representatives, contracts may not
> be concluded on behalf of Civica by email. Please note that
> neither Civica nor the sender accepts any responsibility for
> any viruses and it is your responsibility to scan the email
> and the attachments (if any). All email received and sent by
> Civica may be monitored to protect the business interests of
> Civica.
>
>
>
> --
>
> This email is from Civica Pty Limited and it, together with
> any attachments, is confidential to the intended recipient(s)
> and the contents may be legally privileged or contain
> proprietary and private information. It is intended solely
> for the person to whom it is addressed. If you are not an
> intended recipient, you may not review, copy or distribute
> this email. If received in error, please notify the sender
> and delete the message from your system immediately. Any
> views or opinions expressed in this email and any files
> transmitted with it are those of the author only and may
> not necessarily reflect the views of Civica and do not create
> any legally binding rights or obligations whatsoever. Unless
> otherwise pre-agreed by exchange of hard copy documents
> signed by duly authorised representatives, contracts may not
> be concluded on behalf of Civica by email. Please note that
> neither Civica nor the sender accepts any responsibility for
> any viruses and it is your responsibility to scan the email
> and the attachments (if any). All email received and sent by
> Civica may be monitored to protect the business interests of
> Civica.
>
>
>
> ------------------------------------------------------------------------------
> Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day
> trial. Simplify your report design, integration and deployment - and focus
> on
> what you do best, core application coding. Discover what's new with
> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
> _______________________________________________
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>


-- 
Abdelhadi

[Gwt-openlayers-users] Fwd: Fwd: WFS Operations

[Edwin C. <com...@gm...>]

Hi Cameron,

The WFS is indeed for doing GetFeature calls, sorry if I made it seem like
it isn't. A feature is an object that has spatial properties and may have
non-spatial properties. What you probably want however is GetFeatureInfo,
because then you can use WMS to spit out the map image, and get the
non-spatial properties via GetFeatureInfo. It is possible to to draw up a
map from GetFeature information, but this will only work if your features
are not to complex, because then you have to draw the features client side
(see the WFS examples on http://openlayers.org/dev/examples/). As far as I
know the non-spatial properties are stored on the feature, so you can attach
clickhandlers to those features to pop up information upon a click.

If you have followed the example on the GeoServer side, does that mean you
are working with GWT-OL version 0.2?

There have been a lot of additions in GWT-OL version 0.4. I recommend
downloading version 0.4 and the 0.4 showcase and take a look at that. The
readme in the showcase should help you run it. Better still is to get the
source fromt Mercurial (anonymous clone), because the showcase is somewhat
improved there (no deprecated stuff). Sorry, that there is not more
documentation I can point you at.

Finally, both the WMS GetFeatureInfo as well as the WFS  GetFeature request
presuppose that you have your feature data in one place. Common is to create
a view that combines spatial and non spatial information for a particular
feature and expose that view as a WMS/WFS layer. I don't think that
GeoServer can work with Firebird however (
http://docs.geoserver.org/1.7.x/en/user/data/index.html). I wouldn't see how
a standard WFS server like GeoServer could combine data from a shapefile and
a Firebird database in creating a WFS response. Doesn't your shapefile
contain non-spatial information? The shapefile can store non-spatial
information and GeoServer can expose it as a WMS as well as a WFS.

If you want to read up on using OGC webservices for a web GIS app, then I
suggest to take a look at:
http://www.pragprog.com/titles/sdgis/gis-for-web-developers

That book should be able to take away a lot of questions of how to setup a
WMS or WFS. Once you have those working, you can use GWT-OL currently to
talk to the WMS, and hopefully soon to talk to the WFS. As i said OpenLayers
can talk to WFS services, but I have not implemented that. It is non-trivial
to wrap because it needs a server side proxy. The one with OpenLayers only
works if you are able to run the python cgi script (won't work on windows
without working out how).

Greetings,
Edwin

---------- Forwarded message ----------
From: Cameron Hunt <CH...@ci...>
Date: 2009/8/10
Subject: RE: [Gwt-openlayers-users] Fwd: WFS Operations
To: Edwin Commandeur <com...@gm...>


 Thanks again Edwin,



Yes you are right there should be no use for us to cycle through polygons.
Also if you are not reading any use for WFS from my descriptions then I am
more than happy to stay within the bounds of WMS. My understanding may have
been a bit amiss with WFS as I thought I needed to implement this to make
GetFeature calls etc.



Basically the point I started from was the tutorial document from here
http://geoserver.org/display/GEOSDOC/Google+Web+Toolkit+(GWT),+OpenLayers+and+GeoServer<http://geoserver.org/display/GEOSDOC/Google+Web+Toolkit+%28GWT%29,+OpenLayers+and+GeoServer>

in the hope that I could just extend it and build on it for my own use. It
all seems to work fine for my own WMS\shapefile layer but now there seems to
be (and understandably so) a lack of examples for more complex tasks.



Can I avoid WFS and still get the functionality I need within GWT-OL for
getting feature info etc?



Also we were going to use a Firebird database for the simple fact that we
were familiar with it from our Delphi environment but would you suggest it
might be better to think about another DB so we can take advantage of
storing our spatial data and textual data all in the one place?



Storing all the data including the spatial data in one DB sounds very
appealing but again I would need some guidance as to how to draw and
interrogate the map using GWT-OL.



Sorry to be taking up your valuable time with sorts of beginner questions.
Coming from a Delphi VCL environment is a bit hard to get my head around how
the dots all join up now.



Are there any other user examples available that might be doing some of the
common sorts of tasks we are trying to implement using GWT-OL?



Thanks again



Cameron


 ------------------------------

*From:* Edwin Commandeur [mailto:com...@gm...]
*Sent:* Monday, 10 August 2009 12:08 PM
*To:* gwt...@li...
*Subject:* [Gwt-openlayers-users] Fwd: WFS Operations



Hi Cameron,

First, a correction. I checked and the WFS class  was already in OpenLayers
2.7 and OL versions before that. Although it is true that there were many
enhancements relating to WFS in OpenLayers 2.8.

Anyway, I remember why it is relevant to know about the proxy. For instance,
I work on Windows, and the proxy is a python script that is set up to run
under Linux. The problem is: when the proxy doesn't work, the WFS stuff
doesn't work.

You need a proxy to do WFS requests, because of cross-domain restrictions on
Ajax requests. There are solutions for doing cross-domain GET requests, but
doing cross-domain POST requests can only work with a proxy as far as I
know.

Furthermore, the proxy that comes with OpenLayers is not very sophisticated
and may even present a security risk when it is accessible outside your app.
See also the comments in the proxy.cgi file.

For GWT-OL it makes sense to have a proxy servlet in java. I may need to
look into that. Preferably, I want to keep GWT-OL client-side. Maybe, it is
necessary to start a "GWT-OL server" project that provides server side
components, such as a WFS proxy and a print servlet.

Due to the cross-browser restrictions issue I had not looked deeply into the
WFS.

Now onto what you describe. If you want to shade the map based on what
software version clients are using then you need SLD's. You probably want to
proxy the WMS call that OpenLayers does, and let the proxy do a WMS call
with an SLD that shades the map based on the version of the software. This
is not trivial unfortunetaly. We are using GeoTools for the SLD building in
a custom proxy that is proprietary.

Why would you want to manually loop through polygons on the map? If for
instance the polygons are the states of the USA and they all have a property
CAPITAL, then you would want to store the polygons in a spatially enabled
database (PostGis or Oracle Spatial are the most common ones). A WMS server
could draw a map from those polygons. When someone clicks the map you either
do a getFeatureInfo request on the WMS to get the property, or you pass the
coordinate to the database and let a spatial query sort out in which polygon
the coordinate falls.

I am not reading any use cases for WFS in your mail. WFS is also a bit
tricky, because you can kill the browser if the geometries of your features
are complicated, or if you have to draw a lot of features (that is really a
lot). I have seen that happen, that a getFeature request returns several mb
of reponse, killing the browser.

As an aside, you can also draw your own geometries on the map in a Vector
layer.

Greetings,
Edwin Commandeur

P.S. In case you are wondering: With WMS it is possible to overcome cross
browser restrictions by using the image tag in WMS layers. The src attribute
of the image tag can point at any url.

P.S. P.S. GWT and GWT-OL let you abstract from javascript and html, but that
doesn't mean you don't have to learn javascript and html (or other browser
related technologies). GWT solves many issues, such as using plain java OO
versus a javascript framework specific type of OO, compressing and
optimizing your javascript, make it possible to create modules etc. But
eventually, the code runs in the browser and it helps to know about browser
specific technologies. Especially CSS, but also javascript and html.

 ---------- Forwarded message ----------
From: *Cameron Hunt* <CH...@ci...>
Date: 2009/8/10
Subject: RE: WFS Operations
To: Edwin Commandeur <com...@gm...>

  Thanks Edwin,



I’m happy to beta test anything you want. Just to give you some background
we are just in the early stages of an in house web application to track and
present customer information via a map. We are actually very new to web
development and also Java. We’ve come from a background of Delphi and used
TatukGIS VCL component in our old app which was especially easy to use but
now we are entering a different world.



We would like to do things like shade the map based on what release of our
software customers are on. Also accessing external database information via
a common field (even if this is just manually retrieving from the DB once we
identify the associated polygon on the map). In fact all of our info will be
stored in an external database so rendering the map based on attributes will
be attributes coming from the DB so I’m hoping to be able to do things like
manually loop through the map polygons etc.



GWT-OL certainly looks like the easiest way we’ve found so far without
having learn Javascript and HTML as well.



I’m still coming to terms with understanding WMS and WFS so please forgive
me if I ask any dumb questions.



So when your new changes come through instead of creating a WMS layer I
would create a WFS layer?



Cameron


 ------------------------------

*From:* Edwin Commandeur [mailto:com...@gm...]
*Sent:* Monday, 10 August 2009 08:59 AM
*To:* gwt...@li...
*Cc:* Cameron Hunt
*Subject:* WFS Operations



Hi Cameron,

Like the WMSGetFeatureInfo, the WFS support is also new in OpenLayers 2.8.

The WFS support is high on my list to get working with GWT-OpenLayers, but
currently it is not in GWT-OL. I am just reworking the GWT-OL code and
showcase a little bit (removing warnings and deprecated AddClickListener
stuff), but after that I think the WMSGetFeatureInfo Control and the WFS
layer will be my primary goals. Having good WMS/WFS support is first on the
list, and getting a good Google Maps example a good second.

Would be nice to have you as beta tester of the WMSGetFeatureInfo and WFS
support, when I get to it. I hope so this week.

OpenLayers 2.8 does WFS requests via a cgi proxy to get past the
cross-domain restrictions. As a user you should not concern yourself with
that to much, but for your information...

Greetings,
Edwin

---------- Forwarded message ----------
From: *Cameron Hunt* <CH...@ci...>
Date: 2009/8/10
Subject: RE: [Gwt-openlayers-users] Some general beginners questions
To: Edwin Commandeur <com...@gm...>

Thank you Edwin,



I am using Geoserver so I will look into the WFS operations. Should I be
able to perform these operations easily enough using GWT-Openlayers?



Thanks.



Regards

Cameron


 ------------------------------

*From:* Edwin Commandeur [mailto:com...@gm...]
*Sent:* Monday, 10 August 2009 07:20 AM
*To:* AbdElhadi
*Cc:* Cameron Hunt; gwt...@li...
*Subject:* Re: [Gwt-openlayers-users] Some general beginners questions



Hi Cameron,

*GetFeatureInfo*: Abdelhadi is right about the feature info on a WMS. You
would need a WMS server that supports GetFeatureInfo. GeoServer supports
GetFeatureInfo requests for example, as does MapServer. Be careful: the
GetFeatureInfo response has not been standardized by the OGC.

Since OpenLayers 2.8, OpenLayers has WMSGetFeatureInfo control that
abstracts over several different GetFeatureInfo response formats. I will add
support for that control to GWT-OL.

*Thematic mapping*: That is something I think you would have to achieve
using SLD's (Styled Layer Descriptors). Since SLD's can get quite big, in
our company we wrote a proxy for performing GetMap POST requests with custom
SLD's. That proxy is closed source however. You will have to roll your own
variant.

*Printing*: Printing is always a bit problematic in my experience. You will
probably want to build a PDF server side with the information on the map. If
the map consists only of pictures (WMS layer, Legend graphics) then you can
get quite far with some server side code and a PDF generation framework.
There is one open source printing solution that I know of, and that is the
MapPrintService in the MapFish framework. At the core it is a Java servlet
and right now I am guessing it uses some Java PDF generation library.
Printing vector features is a little more challenging.

A simple solution for printing is to provide a separate page with a clone of
the map in you app, and use the browser to print that. In my experience the
vector features get printed also, but you have little control over the
printing process itself.

Greetings,
Edwin Commandeur

2009/8/7 AbdElhadi <abd...@gm...>

Hi Cameron,

I don't think you can get the feature info from a WMS layer unless the WMS
Server supports the GetFeatureInfo. a WMS is basically just an image.

AS for Thematics, I don't think OL supports that but I am not sure.

Cheers,
-Abdelhadi

On Thu, Aug 6, 2009 at 11:34 PM, Cameron Hunt <CH...@ci...> wrote:

  Hi,



I’ve just started using GWT-Openlayers and so far it looks great. Having
said that I’ve only done a few basic things. I would very much appreciate it
if somebody could give me a couple of quick pointers in the right direction
for the following tasks please?



   - Finding out the information about an object (e.g. polygon) when user
   clicks on map (based on shapefile loaded in as WMS layer)
   - Thematic mapping (e.g. shading all polygons based on an attribute).
   - Printing. How do people provide basic printing to their users?



Thank you.



Regards,

Cameron Hunt
Software Developer
Civica Solutions Pty Limited

Ph: (07) 46393633
Fx: (07) 46393632
ch...@ci...
www.civica.com.au



--

This email is from Civica Pty Limited and it, together with
any attachments, is confidential to the intended recipient(s)
and the contents may be legally privileged or contain
proprietary and private information. It is intended solely
for the person to whom it is addressed. If you are not an
intended recipient, you may not review, copy or distribute
this email. If received in error, please notify the sender
and delete the message from your system immediately. Any
views or opinions expressed in this email and any files
transmitted with it are those of the author only and may
not necessarily reflect the views of Civica and do not create
any legally binding rights or obligations whatsoever. Unless
otherwise pre-agreed by exchange of hard copy documents
signed by duly authorised representatives, contracts may not
be concluded on behalf of Civica by email. Please note that
neither Civica nor the sender accepts any responsibility for
any viruses and it is your responsibility to scan the email
and the attachments (if any). All email received and sent by
Civica may be monitored to protect the business interests of
Civica.



------------------------------------------------------------------------------
Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day
trial. Simplify your report design, integration and deployment - and focus
on
what you do best, core application coding. Discover what's new with
Crystal Reports now.  http://p.sf.net/sfu/bobj-july
_______________________________________________
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-- 
Abdelhadi

------------------------------------------------------------------------------
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what you do best, core application coding. Discover what's new with
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_______________________________________________
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--

This email is from Civica Pty Limited and it, together with
any attachments, is confidential to the intended recipient(s)
and the contents may be legally privileged or contain
proprietary and private information. It is intended solely
for the person to whom it is addressed. If you are not an
intended recipient, you may not review, copy or distribute
this email. If received in error, please notify the sender
and delete the message from your system immediately. Any
views or opinions expressed in this email and any files
transmitted with it are those of the author only and may
not necessarily reflect the views of Civica and do not create
any legally binding rights or obligations whatsoever. Unless
otherwise pre-agreed by exchange of hard copy documents
signed by duly authorised representatives, contracts may not
be concluded on behalf of Civica by email. Please note that
neither Civica nor the sender accepts any responsibility for
any viruses and it is your responsibility to scan the email
and the attachments (if any). All email received and sent by
Civica may be monitored to protect the business interests of
Civica.



--

This email is from Civica Pty Limited and it, together with
any attachments, is confidential to the intended recipient(s)
and the contents may be legally privileged or contain
proprietary and private information. It is intended solely
for the person to whom it is addressed. If you are not an
intended recipient, you may not review, copy or distribute
this email. If received in error, please notify the sender
and delete the message from your system immediately. Any
views or opinions expressed in this email and any files
transmitted with it are those of the author only and may
not necessarily reflect the views of Civica and do not create
any legally binding rights or obligations whatsoever. Unless
otherwise pre-agreed by exchange of hard copy documents
signed by duly authorised representatives, contracts may not
be concluded on behalf of Civica by email. Please note that
neither Civica nor the sender accepts any responsibility for
any viruses and it is your responsibility to scan the email
and the attachments (if any). All email received and sent by
Civica may be monitored to protect the business interests of
Civica.



--

This email is from Civica Pty Limited and it, together with
any attachments, is confidential to the intended recipient(s)
and the contents may be legally privileged or contain
proprietary and private information. It is intended solely
for the person to whom it is addressed. If you are not an
intended recipient, you may not review, copy or distribute
this email. If received in error, please notify the sender
and delete the message from your system immediately. Any
views or opinions expressed in this email and any files
transmitted with it are those of the author only and may
not necessarily reflect the views of Civica and do not create
any legally binding rights or obligations whatsoever. Unless
otherwise pre-agreed by exchange of hard copy documents
signed by duly authorised representatives, contracts may not
be concluded on behalf of Civica by email. Please note that
neither Civica nor the sender accepts any responsibility for
any viruses and it is your responsibility to scan the email
and the attachments (if any). All email received and sent by
Civica may be monitored to protect the business interests of
Civica.

[Gwt-openlayers-users] Fwd: WFS Operations

[Edwin C. <com...@gm...>]

Hi Cameron,

First, a correction. I checked and the WFS class  was already in OpenLayers
2.7 and OL versions before that. Although it is true that there were many
enhancements relating to WFS in OpenLayers 2.8.

Anyway, I remember why it is relevant to know about the proxy. For instance,
I work on Windows, and the proxy is a python script that is set up to run
under Linux. The problem is: when the proxy doesn't work, the WFS stuff
doesn't work.

You need a proxy to do WFS requests, because of cross-domain restrictions on
Ajax requests. There are solutions for doing cross-domain GET requests, but
doing cross-domain POST requests can only work with a proxy as far as I
know.

Furthermore, the proxy that comes with OpenLayers is not very sophisticated
and may even present a security risk when it is accessible outside your app.
See also the comments in the proxy.cgi file.

For GWT-OL it makes sense to have a proxy servlet in java. I may need to
look into that. Preferably, I want to keep GWT-OL client-side. Maybe, it is
necessary to start a "GWT-OL server" project that provides server side
components, such as a WFS proxy and a print servlet.

Due to the cross-browser restrictions issue I had not looked deeply into the
WFS.

Now onto what you describe. If you want to shade the map based on what
software version clients are using then you need SLD's. You probably want to
proxy the WMS call that OpenLayers does, and let the proxy do a WMS call
with an SLD that shades the map based on the version of the software. This
is not trivial unfortunetaly. We are using GeoTools for the SLD building in
a custom proxy that is proprietary.

Why would you want to manually loop through polygons on the map? If for
instance the polygons are the states of the USA and they all have a property
CAPITAL, then you would want to store the polygons in a spatially enabled
database (PostGis or Oracle Spatial are the most common ones). A WMS server
could draw a map from those polygons. When someone clicks the map you either
do a getFeatureInfo request on the WMS to get the property, or you pass the
coordinate to the database and let a spatial query sort out in which polygon
the coordinate falls.

I am not reading any use cases for WFS in your mail. WFS is also a bit
tricky, because you can kill the browser if the geometries of your features
are complicated, or if you have to draw a lot of features (that is really a
lot). I have seen that happen, that a getFeature request returns several mb
of reponse, killing the browser.

As an aside, you can also draw your own geometries on the map in a Vector
layer.

Greetings,
Edwin Commandeur

P.S. In case you are wondering: With WMS it is possible to overcome cross
browser restrictions by using the image tag in WMS layers. The src attribute
of the image tag can point at any url.

P.S. P.S. GWT and GWT-OL let you abstract from javascript and html, but that
doesn't mean you don't have to learn javascript and html (or other browser
related technologies). GWT solves many issues, such as using plain java OO
versus a javascript framework specific type of OO, compressing and
optimizing your javascript, make it possible to create modules etc. But
eventually, the code runs in the browser and it helps to know about browser
specific technologies. Especially CSS, but also javascript and html.


---------- Forwarded message ----------
From: Cameron Hunt <CH...@ci...>
Date: 2009/8/10
Subject: RE: WFS Operations
To: Edwin Commandeur <com...@gm...>


 Thanks Edwin,



I’m happy to beta test anything you want. Just to give you some background
we are just in the early stages of an in house web application to track and
present customer information via a map. We are actually very new to web
development and also Java. We’ve come from a background of Delphi and used
TatukGIS VCL component in our old app which was especially easy to use but
now we are entering a different world.



We would like to do things like shade the map based on what release of our
software customers are on. Also accessing external database information via
a common field (even if this is just manually retrieving from the DB once we
identify the associated polygon on the map). In fact all of our info will be
stored in an external database so rendering the map based on attributes will
be attributes coming from the DB so I’m hoping to be able to do things like
manually loop through the map polygons etc.



GWT-OL certainly looks like the easiest way we’ve found so far without
having learn Javascript and HTML as well.



I’m still coming to terms with understanding WMS and WFS so please forgive
me if I ask any dumb questions.



So when your new changes come through instead of creating a WMS layer I
would create a WFS layer?



Cameron


 ------------------------------

*From:* Edwin Commandeur [mailto:com...@gm...]
*Sent:* Monday, 10 August 2009 08:59 AM
*To:* gwt...@li...
*Cc:* Cameron Hunt
*Subject:* WFS Operations



Hi Cameron,

Like the WMSGetFeatureInfo, the WFS support is also new in OpenLayers 2.8.

The WFS support is high on my list to get working with GWT-OpenLayers, but
currently it is not in GWT-OL. I am just reworking the GWT-OL code and
showcase a little bit (removing warnings and deprecated AddClickListener
stuff), but after that I think the WMSGetFeatureInfo Control and the WFS
layer will be my primary goals. Having good WMS/WFS support is first on the
list, and getting a good Google Maps example a good second.

Would be nice to have you as beta tester of the WMSGetFeatureInfo and WFS
support, when I get to it. I hope so this week.

OpenLayers 2.8 does WFS requests via a cgi proxy to get past the
cross-domain restrictions. As a user you should not concern yourself with
that to much, but for your information...

Greetings,
Edwin

---------- Forwarded message ----------
From: *Cameron Hunt* <CH...@ci...>
Date: 2009/8/10
Subject: RE: [Gwt-openlayers-users] Some general beginners questions
To: Edwin Commandeur <com...@gm...>

  Thank you Edwin,



I am using Geoserver so I will look into the WFS operations. Should I be
able to perform these operations easily enough using GWT-Openlayers?



Thanks.



Regards

Cameron


 ------------------------------

*From:* Edwin Commandeur [mailto:com...@gm...]
*Sent:* Monday, 10 August 2009 07:20 AM
*To:* AbdElhadi
*Cc:* Cameron Hunt; gwt...@li...
*Subject:* Re: [Gwt-openlayers-users] Some general beginners questions



Hi Cameron,

*GetFeatureInfo*: Abdelhadi is right about the feature info on a WMS. You
would need a WMS server that supports GetFeatureInfo. GeoServer supports
GetFeatureInfo requests for example, as does MapServer. Be careful: the
GetFeatureInfo response has not been standardized by the OGC.

Since OpenLayers 2.8, OpenLayers has WMSGetFeatureInfo control that
abstracts over several different GetFeatureInfo response formats. I will add
support for that control to GWT-OL.

*Thematic mapping*: That is something I think you would have to achieve
using SLD's (Styled Layer Descriptors). Since SLD's can get quite big, in
our company we wrote a proxy for performing GetMap POST requests with custom
SLD's. That proxy is closed source however. You will have to roll your own
variant.

*Printing*: Printing is always a bit problematic in my experience. You will
probably want to build a PDF server side with the information on the map. If
the map consists only of pictures (WMS layer, Legend graphics) then you can
get quite far with some server side code and a PDF generation framework.
There is one open source printing solution that I know of, and that is the
MapPrintService in the MapFish framework. At the core it is a Java servlet
and right now I am guessing it uses some Java PDF generation library.
Printing vector features is a little more challenging.

A simple solution for printing is to provide a separate page with a clone of
the map in you app, and use the browser to print that. In my experience the
vector features get printed also, but you have little control over the
printing process itself.

Greetings,
Edwin Commandeur

2009/8/7 AbdElhadi <abd...@gm...>

Hi Cameron,

I don't think you can get the feature info from a WMS layer unless the WMS
Server supports the GetFeatureInfo. a WMS is basically just an image.

AS for Thematics, I don't think OL supports that but I am not sure.

Cheers,
-Abdelhadi

On Thu, Aug 6, 2009 at 11:34 PM, Cameron Hunt <CH...@ci...> wrote:

  Hi,



I’ve just started using GWT-Openlayers and so far it looks great. Having
said that I’ve only done a few basic things. I would very much appreciate it
if somebody could give me a couple of quick pointers in the right direction
for the following tasks please?



   - Finding out the information about an object (e.g. polygon) when user
   clicks on map (based on shapefile loaded in as WMS layer)
   - Thematic mapping (e.g. shading all polygons based on an attribute).
   - Printing. How do people provide basic printing to their users?



Thank you.



Regards,

Cameron Hunt
Software Developer
Civica Solutions Pty Limited

Ph: (07) 46393633
Fx: (07) 46393632
ch...@ci...
www.civica.com.au



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