[geotk] [Newbie] Image download and polygon drawing

[Martin Desruisseaux]

Hello Sam

Sam B a écrit :
> What I would like to do, is getting a map from a WMS server, store it on 
> my harddisk (maybe via a serializable class) and display it on the 
> screen. Then I would like to draw some polygons on it, and finally 
> calculate their area.
> 
> Here are my questions :
> 
> - Is there a small example for getting an image from a WMS server ?
> - What is the best way to draw some polygons and shape on it ? Just to 
> use simple AWT objects ? I saw there's a org.geotoolkit.display.shape 
> <http://www.geotoolkit.org/apidocs/org/geotoolkit/display/shape/package-summary.html> 
> package*, *but it looks much more like an extension to some existing 
> (AWT?) objects

Before attempting to suggest an approach, I need to explain an important aspect 
of the Geotoolkit project. This project is splitted in two parts (both of them 
open-source and available at http://hg.geotoolkit.org):

* Geotoolkit
* Geotoolkit-pending

The javadoc available online is the one of Geotoolkit only. They are the most 
stable parts, polished, careful on compatibility (if a methods need to be 
removed, if it first deprecated for at least one release cycle), released every 
month with a list of API changes, etc.

Geotoolkit-pending is in a much more flux state, under high development 
activity, with more frequent API changes, its javadoc is not yet published on 
the web. Anyone is welcome to use geotoolkit-pending, but should be aware that 
the risk (compatibility break, etc.) is slightly higher than when using the 
stable geotoolkit part.

The plan is to gradually move code from Geotoolkit-pending to Geotoolkit when 
they mature.

We actually provide a full renderer engine much more powerfull than what the 
above-cited org.geotoolkit.display package javadoc show. This renderer engine 
does not show up in the javadoc because it lives in Geotoolkit-pending for now. 
The easiest way to get the binary JARs is through Maven:

     http://maven.geotoolkit.org/org/geotoolkit/pending/

In order to get the code (which is currently the only form of documentation), 
for now there is only the Mercurial way. Mercurial is an open-source Distributed 
Versioning System than you can get from http://mercurial.selenic.com/wiki/. Once 
installed, executing the following command-line will give you a copy of all the 
geotoolkit-pending code (you can also browse the link on-line if you prefer):

     hg clone http://hg.geotoolkit.org/geotoolkit-pending/

The renderer is maintained by Johan Sorel, who is in vacation for the next 2 or 
3 weeks. If you are lucky, he reads his email during his vacation and can give 
you some hints :).

For the WMS part, I will ask to my co-worker and get back later.

	Regards

		Martin