A Rasterizer transforms vector geometries in gridd information datas.
author  Johann Sorel

return

Reset image on given area.
param  area

Rasterize given geometry.
The produced image contains a byte for each pixel.
0 is for a pixel outside the geometry
255 is for a pixel completely inside the geometry
1-254 may be used to indicate partial inclusion
param  geom
return  Image, this image is a 1 band byte image