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I checked the official GeoTIFF documentations and there is no reference to color maps. Regardless, I see color maps or tables referenced everywhere, including in other questions.

I am aware that a GeoTIFF can be converted into a RGBA GeoTIFF, but this would simply be a completely different GeoTIFF with the original information lost, unless the legend is also saved separately.

I am asking if there is a way to not change the values of the GeoTIFF and to include in it a threshold based color map (or maybe a rule based one) that can be later interpreted by most software correctly.

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  • GDAL provides the possibility of adding a color table to a GeoTIFF file. Take a look at gis.stackexchange.com/a/325751/86131.
    – Marcelo Villa
    Commented Aug 9, 2020 at 20:29
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    The GeoTIFF standard only specifies georeferencing docs.opengeospatial.org/is/19-008r4/19-008r4.html#_scope. Colour table support is software dependent.
    – user2856
    Commented Aug 9, 2020 at 21:49
  • @MarceloVilla-Piñeros, just based on the input parameters SetColorEntry only allows an integer value and a triple of integers for the rgb. Apart from the fact that I would need to specify the very same colour for a lot of values for a threshold based visualization, I would also need to convert my values to integers and in effect, lose the original values. The way I see it, this would not be a color table linked to values, but just colors stored in an indexed way. If you're lucky to match the Index palette to your values, then it works, but it's not a general purpose color table.
    – Andrei
    Commented Aug 10, 2020 at 12:17
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    TIFF supports color tables and GeoTIFF does not change that awaresystems.be/imaging/tiff/tifftags/colormap.html
    – user30184
    Commented Aug 10, 2020 at 23:15
  • @user30184 That is a very limited color map, and it doesn't work with all tiffs (e.g. tiffs with float values). Also, the lookup table needs to be explicit. This is, at best, a very limited implementation of color tables. I can't know the intentions of this implementations, but it seems to be just a compressing technique using colormaps, and not a true colormap implementation.
    – Andrei
    Commented Aug 21, 2020 at 10:05

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