Changes between Initial Version and Version 5 of Ticket #2625


Ignore:
Timestamp:
Oct 24, 2008, 11:47:10 AM (16 years ago)
Author:
warmerdam
Comment:

Updated main bug description.

I agree with Even's analysis and it will be difficult to correct this without changes to libtiff that make it possible to remove a tag from an existing directory. I'm going to leave this open but I do not anticipate it being resolved in the near future.

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  • Ticket #2625

    • Property Status new → assigned
    • Property Component PerlBindings → GDAL_Raster
    • Property Summary Setting the geotransform seems to fail in some cases → GeoTIFF geotransform update fails in some cases
    • Property Priority normal → low
    • Property Keywords gtiff added
    • Property Owner changed from Ari Jolma to warmerdam
    • Property Type defect → enhancement

  • Ticket #2625 – Description

    initial v5  
    1 I managed to change the geotransform (t[5] specifically) of a geotiff from 2 to -2, but changing it back did not work. Need to investigate.
     1An attempt to update a GeoTIFF with a tiepoint+scale (normal geotransform) with one that requires ModelTransformationTag results in no apparent change because the tiepoint+scale values are not (and really cannot be) removed the way the libtiff api works.
     2
     3For instance, if we do so we can end up with a file like:
     4{{{
     5   Tagged_Information:
     6      ModelTiepointTag (2,3):
     7         0                0                0               
     8         440720           3751320          0               
     9      ModelPixelScaleTag (1,3):
     10         60               60               0               
     11      ModelTransformationTag (4,4):
     12         2                0                0                0               
     13         0                3                0                0               
     14         0                0                0                0               
     15         0                0                0                1     
     16}}}
     17Then the GTiff driver just ignores the modeltransformtag since the tiepoint+pixelscale is still present. 
     18