[OSGeo-Discuss] clip raster by a circle in map coordinates

[Marc Peterson]

I need to clip an input raster data set by a circle and write the extracted
cells to a new raster.  Then I have to repeat 35,387 times, so any solution
needs to be scriptable.  The dream solution would be to issue a command with
arguments specifying the X coordinate, Y coordinate, and radius.  I assume,
however, that I'll need to do some sort of intersect operation using either
a mask matrix, a rasterized vector circle, or some XML that defines the
circle.

Is this possible?  Any script/software recommendations?  I started looking
in to GRASS r.circle but haven't yet gotten very far.  Basically, I want to
do what the ArcGIS "Extract by Circle" tool will do, but I want to do it
much more quickly and without ESRI.

Thanks,
Marc Peterson
Spatial Analyst
Carolina Population Center, UNC Chapel Hill