Re: [Gwt-openlayers-devl] Request for information about GWT-OpenLayers

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

Hi Nishant,

GWT-OpenLayers is a wrapper library for the OpenLayers Javascript
library, so GWT projects can use OpenLayers functionality without
having to implement the JSNI wrapper code themselves.

In an ideal world it would be a plain GWT port of OpenLayers, but for
now it leverages the momentum of OpenLayers.

Add 1) There is currently no overview of which functionality is
wrapped by GWT-OL exactly. However, most of the stuff for working with
OGC WMS/WFS webservices and vector layers has been wrapped. Recently
also the vector feature manipulations controls (modify, drag, rotate
features) have been wrapped and the WFS protocol has been implemented.
The GWT-OL codebase has evolved mainly on the basis of the needs of
the developers. There has been some work on third-party layers
(Google, ArcGiS), but I cannot tell you the status of the support for
these layers, as I do not have showcase examples for them yet and have
not used them myself.

Add 2) First of all GWT-OL wraps OpenLayers, so bugs in OpenLayers are
also in GWT-OL. There are no pressing bugs that I can think of in
GWT-OL specifically. The most pressing things are extending the
showcase with more examples and providing more documentation to users
of the API. My current focus is adding a simple open proxy
implementation, which should make it easy to use WFS protocol and make
a showcase example for that.
There is off course more functionality of OpenLayers that I'd like to
see wrapped, but the infrastructure for wrapping OpenLayers is good in
place.

Add 3) MapFish is a solution with client and server side components.
The client side components are build on top of OpenLayers and recently
GeoExt, which itself uses OpenLayers for the map component and Ext-JS
for the GUI components. GeoExt in turn is building stuff to interface
with the MapFish print service. GeoExt and MapFish provide stuff for
building GIS applications that is not in OpenLayers, but tie you into
Ext-JS for the GUI.
The only true comparison you can make is GWT-OpenLayers with
OpenLayers. If you're doing everything in JavaScript then you should
be using OpenLayers and if you are also using Ext-JS then have a look
at GeoExt and MapFish. However, if you are developing with GWT, which
itself gives you a lof of benefits over developing in Javascript (see
for example: http://www.keylimetie.com/Blog/2009/3/11/why-choose-gwt/),
then you cannot simply use OpenLayers, but need GWT-OpenLayers.

Ad 4) There is no roadmap past the one for version 0.5
(https://sourceforge.net/apps/trac/gwt-openlayers/roadmap), but the
ultimate goals are:
- to wrap all OpenLayers offers
- provide tight GWT integration (using GWT widgets in popups etc)

In tandem to those goals it would be nice if a plain GWT web mapping
library gets of the ground. That would preferably be when Vector
Graphics hit GWT to implement Vector Layers. There is already a
GWTCanvas in incubator:
http://code.google.com/p/google-web-toolkit-incubator/wiki/GWTCanvas
and there are other iniatives like:
http://code.google.com/p/gwt-canvas/
http://code.google.com/p/gwt-g2d/
http://vaadin.com/web/hene/wiki/-/wiki/Main/GWT+Graphics

Greetings,
Edwin

On 10 February 2010 14:15, nishant verma <nis...@gm...> wrote:
> Hi
>
>    I am currently a developer in OpenXdata project
> http://www.openxdata.org/. OpenXdata is an open-source, enterprise,
> end-to-end software solution for any type of forms based data collection and
> management using mobile devices and web forms.
>
>              We are now looking for developing a web-based GIS application
> for OpenXdata. We were searching for various open-source GIS web frameworks,
> when we came across your project at
> http://sourceforge.net/projects/gwt-openlayers/. We have also looked at
> OpenLayers, MapFish etc. But on sourceforge, we couldn't find answers to
> some questions we have. In this context, on behalf of OpenXdata, I would
> like to ask you a few questions:
>
> 1) What all functionalities of OpenLayers does GWT-OpenLayers support? On
> this link
> http://geoserver.org/display/GEOSDOC/Google+Web+Toolkit+(GWT),+OpenLayers+and+GeoServer,
> we could find a mention of some of the functionalities, but seems like this
> is an old documentation and refers to GWT-OpenLayers 0.1.
>
> 2) What are the most pressing bugs that GWT-OpenLayers is facing?
>
> 3) What are the key benefits when compared to other frameworks like MapFish?
>
> 4) What is the road map for this project? Does it strive to provide all the
> functionality of OpenLayers in future versions?
>
>    I will be grateful to get a reply. Please feel free to ask any questions.
>
> Regards,
> Nishant
>