Re: [Geotools-gt2-users] Getting world coordinates by Mouseclick, Mousebehaviour on StyledMapPane

[Bernhard K. <bka...@li...>]

Martin Desruisseaux wrote:

>> 2. I want to change this behaviour to pan the map. So, when moving 
>> the mouse, the map also moves, but doesn't zoom or anything else. Is 
>> this possible?
>
> You can create yours own subclass of StyledMapPane and override the 
> following method:
>
>     protected void mouseSelectionPerformed(Shape area) {
>     }

thanks, I've found it. I think I'll try it by altering the preferredArea 
or the mapPane

>>> And another question: As already mentioned, I'm using the methods as 
>>> in the Spearfish Sample, which uses J2D-renderer. I experienced 
>>> OutOfMemoryExceptions when dealing with larger shapefiles (3x 30 
>>> MB). Is there a possibility to avoid that?
>>
>
> Technically yes, but it is hard to use at this time.
>
> There is some chances that the shapefile datastore stores the 
> geometries as JTS object with arrays of CoordinatePoint. This storage 
> scheme is expensive. You can "compress" them, but with a cost: the 
> lost of the underlying JTS geometries. Explanation:
>
> J2D renderer internally stores all geometries as 
> org.geotools.renderer.geom.Geometry objects using an abstract 
> PointArray structure. The point array may be JTS's Coordinate[] array, 
> a plain double[] array, etc. The idea is to switch from the 
> Coordinate[] representation to a float[] representation.
>
> We first need to find the underlying Geometry objects. One possible 
> way is to invokes MapPane.getRenderer().getLayers(). Then iterates 
> through those layers and search for "if (layer instanceof 
> RenderedGeometries)". Invokes RenderedGeometries.getGeometry(). You 
> should not have a GeometryCollection (maybe not the only one, the 
> search should continue for other layers).
>
> Invoke Geometry.compress(CompressionLevel.DIRECT_AS_FLOATS). If you 
> get an UnmodifiableGeometryException, try to clone the geometry before 
> to compress it.
>
> Set the new geometry to the RenderedGeometries layer.
>
> Make sure that there is no reference to the original JTS geometry 
> floating around (you may need to checks in a profiler to make sure 
> that their memory is reclaimed).

Maybe this is easier to realise with the LiteRenderer?
Is there btw. any Tutorial showing howto Render Shapefiles with the 
LiteRenderer? I only found Tutorials which rendered manually generated 
FeatureCollections and have no idea how to render Shapefiles with 
LiteRenderer...

Bernhard