Antonio Valentino wrote:
Anyway, IMHO the point here is not to decide if we have to *modify* the diff function so that it returns abs(b1-b2). Greg asked to add a new one ( abs(b1-b2) ) to the *base set* of pixel functions. Stated that there is no technical difficulty to do this I'm wondering what is the Frank's mind about the question.
Antonio, I think including abs(b1-b2) just demonstrates that we haven't come up with a convenient way of stacking more basic operations (difference and abs). Honestly, I'm a bit ambivalent about fleshing out the use of pixel operations in VRT files and I've never used them myself. I think I would prefer to wait for a more generalized expression evaluation mechanism for VRT or possibly as a distinct driver. However, if there are other GDAL developers keen on this functionality, and willing to take responsibility for integration, documentation and support then I'm willing to let them proceed. Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Programmer for Rent _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev