[mapserver-users] Color filled transparent polygons

[Reinoud Bokhorst]

Hi,
I have a PostGIS table with about 12000 polygons scattered around the globe. The polygons outline areas where I have particular model data. To get an impression about the data density, I want to plot the polygons with a fill color and a high transparency value. This would mean that the colour on the map gets darker depending on how many polygons overlap at a particular location because the color values will add up. 

I can do this for example in QGIS but not in Mapserver. It requires that the polygons themselves are drawn using a transparency value but it seems that mapserver first draws all polygons and them applies the transparency value to the resulting image. Is there a solution for this?

Reinoud Bokhorst