[gdal-dev] crop a non-square subwindow?

[Wendell Turner]

On Thu, Mar 10, 2011 at 05:17:39PM -0500, Frank Warmerdam wrote:
> On 11-03-10 05:07 PM, Wendell Turner wrote:
> >Is there a way to force pixels outside of the cropping
> >polygon to be 'not there', or transparent?  Is there a burn
> >value that indicates that?
> 
> Another approach is to use -dstalpha to add an alpha channel to the output.

That worked fine.  Mapserver/OpenLayers likes it that way.

Wendell