[GRASS-user] Creating a raster with an alpha channel

[Gregory Penn]

This question is directly related to my previous one, in which I described the overall visualization that I'm trying to achieve.

I've managed to create a display of my raster data that looks more or less like I want, i.e. masked with the appropriate vector and color mapped. It occurred to me that if I could create a raster with an alpha channel using the mask, such that the areas that are masked become null or no value pixels, then I might be able to use r.blend with that raster and my base map raster to get the effect that I'm trying for.

I also have no idea how the d.* and r.* modules deal with alpha channels and would welcome some direction to appropriate documentation.

Cheers,
Gregory