gdalwarp with SKIP_NOSOURCE option

[anilkumarputti]

Anil Kumar Putti wrote:

Dear Frank,

With reference to the discussion on gdalwarp with SKIP_NOSOURCE option, I have placed the output files (output.rar, screenshot.rar) in FTP (ftp.navionicseng.com username = "anilputti" password = "anilputti"). In that "out.tif" file is generated from gdalwarp(refer attached file for options) and its file size is 71,079KB, but is was supposed to come for the given coverage as nearly 283,000KB. Refer "screenshot.png" for the Global mapper view of this image.

I have converted the "out.tif" file using "gdal_translate", the output file is "out3.tif". Now if we see the "out3.tif" file the filesize is 283,727KB and we are able to see the correct output in Global Mapper. Refer "screenshot3.png" for the Global mapper view of this image .

Can you please help me to understand what's wrong in this.

Anil,

The GDAL GeoTIFF driver supports sparse GeoTIFF files. That is file where some tiles are completely missing. When you do a gdalwarp and there is no input data for some output tiles, those output tiles will never get written.

GDAL applications, like OpenEV, and gdal_translate support such files as input but many other applications will not support this.

One solution, as you have done, is to gdal_translate the result to produce something universally readable.

I believe this problem is just introduced when using the SKIP_NOSOURCE option.

I'd appreciate it if you could file a bug in the GDAL bug tracker including this explanation. I really need to make all this more bulletproof.

Best regards, Frank