gdalbuildvrt does not support positive NS resolution when based off pixel coordinates

[abarton]

When coordinates are based on pixels which increase positively as you go down, this causes an error in gdalbuildvrt because it can't handle positive NS resolutions.

gdalbuildvrt does not support positive NS resolution.

Attached is a sample file that demonstrates the issue:

e.g. gdalbuildvrt blank_image.vrt blank_image.tif

[Even Rouault]

What is the use case of this ? Do you have georeferenced images that can be mosaiced and have positive NS resolution ? Your sample is just a non-georeferenced image, which makes no sense to try mosaicing

[abarton]

I have a number of VRT bands that compose one imagery product. I'm trying to combine the bands and then geo-reference them. Currently I must geo-reference each band before combining them which introduces complexity and overhead.

[Even Rouault]

I'm trying to understand your last message, but I'm not sure to have gotten it. My interpretation is that you'll plan to use the -separate option of gdalbuildvrt to combine several ungeoreferenced single-band images into a VRT and then georeference the VRT ? Or is it something else ?

Maybe you could give example of the command lines you would use if gdalbuildvrt did what you want, and give the output of gdalinfo on a few of your input images.

[abarton]

You are correct, I am trying to combine several non-georeferenced single-band images into a VRT and then georeference the VRT.

I'm attaching a couple of text files with output from gdalinfo on the input images.

My basic use case would be :

gdalbuildvrt -separate <output_vrt> <input_vrt_files>

[Even Rouault]

r18888 /trunk/gdal/apps/gdalbuildvrt.cpp: gdalbuildvrt : support stacking ungeoreferenced images when using -separate, provided they have the same size (#3432)

r18889 /trunk/autotest/utilities/test_gdalbuildvrt.py: Test gdalbuildvrt -separate with ungeoreferenced images (#3432Ã)