Implementing rendering support for JGrass maps

Raster maps

A first version of the renderer has been created. A lot has to be done yet, but... isn't that very nice? Aspect map and elevation map taken from a JGRASS database drawn with alpha blending under the shapefiles of roads and rivers. I feel good! I knew that I would!

known problems

• at very high zoom the mouse position isn't equal to the drawn pixel position. That is due to the fact that the pixel is drawn always as a whole, but the viewregion is not updated to the occurring shift.
• when I close and reopen udig, the GRASS database isn't in the catalog again (shapefiles for example are) and the layers loaded in the previous session are broken kids.

Sites maps

A first very simple renderer was implemented for sites file. It renders a point and the label.

Vector maps

This wil be a problem, since there is no code to read those binary formats. That is a bit tricky and I don't know who would be interested in supplying founds to support this. Please drop me an email if you are!
The vector maps are for now shown in the catalog, but are not loadable.