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From: Edwin C. <com...@gm...> - 2009-08-09 22:58:45
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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. |
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From: Edwin C. <com...@gm...> - 2009-08-10 02:08:21
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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. |
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From: Edwin C. <com...@gm...> - 2009-08-10 10:22:21
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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 _______________________________________________ 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. -- 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. |
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From: AbdElhadi <abd...@gm...> - 2009-08-10 19:32:25
|
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 |
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From: Edwin C. <com...@gm...> - 2009-08-10 21:35:41
|
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 > |
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