[Gdal-dev] gdal_translate image grow

[Frank Warmerdam]

Norman Barker wrote:
 > Hi,
 >
 > I have managed to get this working with VRT raster files, they are
 > seriously cool and I can program them from python forming a basic WMS.
 >
 > However when I sample from a smaller image to a larger image with
 > greater spatial extents I use a kernel filter.  It seems that the kernel
 > filter doesn't stop in the y-axis and continues for the length of the
 > image (see attached).

Norman,

Can you provide me with a .vrt and data file that demonstrate this problem?
Does it happen only with mapserver, or also just doing a gdal_translate from
the .vrt?   I suspect a bug in need of fixing.

 > Is this something that anyone else has come across? Also how do I make
 > the output png have transparent values, I have tried -a_nodata 0?

I think you are supposed to be able to set TRANSPARENT ON in the PNG
outputformat declaration to enable transparency.  If you are pulling
from mapserver via WMS there is a TRANSPARENT=ON option that should
turn this on.  If this doesn't work let me know the details and I'll see
what I can figure out.

Best regards,
-- 
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