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cogeotiff / rio-cogeo

Cloud Optimized GeoTIFF creation and validation plugin for rasterio
https://cogeotiff.github.io/rio-cogeo/
BSD 3-Clause "New" or "Revised" License
308 stars 42 forks source link

Fix for issue #281 COG validation fails for sparse edge tiles #282

Closed mpadillaruiz closed 6 months ago

mpadillaruiz commented 7 months ago

281

The rio-cogeo validator returns False even though it is a valid COG when there are sparse edge tiles in the file and/or overviews.

This was because the overviews are stored as sparse and the validator checks for the first tile offset of each overview (BLOCK_OFFSET_0_0 tag). Since there are sparse edge tiles, this value is zero, and it cannot verify that the overviews are in the right order, even though they are.

I changed the code to iterate over BLOCK_OFFSET_x_y based on the number of tile rows/columns for the main file and overviews. This makes sure that the data_offset variable gets populated if there is an offset after all the sparse tiles.

Added a new test that checks for a sparse image with sparse tiles on the edges. I also added the tif image for the test.

vincentsarago commented 6 months ago

thanks a lot @mpadillaruiz 🙏