[Geotiff] data types in bands
Frank Warmerdam
warmerdam at pobox.com
Mon Jun 22 20:34:50 EST 2009
Kyle Shannon wrote:
> Thanks Frank,
> We are changing our input file type from a proprietary type to a well
> supported/maintained data type. GeoTiffs seemed the obvious choice.
> Our files can have 3, 5, 6, or 8 bands. Is there a way to specify a
> band is empty? We would like to keep the number of bands constant to
> allow user defined bands (bands 9 - n). We were going to user a
> GDT_Byte for those bands to identify them as 'NoData'. Is there a way
> to identify 'empty' bands in a geotiff, or is it even worth it to try?
Kyle,
There is no standard way to indicate that a band is considered to be all
nodata. Were you planning to store blank data for all the unused bands
on disk?
Further to my last message, I should add that libtiff and GDAL do not
support mixed data types in GeoTIFF.
If you were to store the data with PLANARCONFIG_SEPARATE, all zeros
for unused bands and a run length encoding compression like LZW the
unused bands would take very little space but would otherwise continue
to exist.
Best regards,
--
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I set the clouds in motion - turn up | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | Geospatial Programmer for Rent
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