[Geotiff] Linear Units of Projections Parameters

Frank Warmerdam warmerdam at pobox.com
Sat Feb 25 07:21:52 PST 2006


Folks,

What are peoples opinions on how the units of linear quantities
like false easting and northing should be interpreted in a GeoTIFF file?

Reviewing the specification (ie. the definition of ProjFalseEastingGeoKey
in 2.7.2 of the specification) it seems clear that the false easting and
northing should be in the units defined by ProjLinearGeoKey.

But listgeo's normalized parameter report, GDAL, and a variety of other
commercial software packages all seem to make the assumption that false
easting and northing are always in meters.

I have created a bug report against the specification about this topic, though
it may just be that libgeotiff, GDAL and various other packages need to be
fixed.  I am worried if alot of packages get it wrong, and no one gets it
right (other than OSSIM so far) that we might cause more problems by changing
the common convention.

   http://bugzilla.remotesensing.org/show_bug.cgi?id=1094

Best regards,
-- 
---------------------------------------+--------------------------------------
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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