[gdal-dev] multi-dimensional coordinate variables

Frank Warmerdam warmerdam at pobox.com
Thu Apr 9 13:17:47 EDT 2009


Aaron Sims wrote:
> All,
> 
> I am trying to view a netcdf file in grass via gdal.  The netcdf data is 
> on a projected grid so the latitudes and longitudes are are unique at 
> each point (i.e. 2D coordinate variables).
> gdal  doesnt seem to understand the georeferencing information whn I try 
> to follow the CF-1.0 specs on multi-dimensional coordinate variables,
> http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.0/cf-conventions.html#id2888361
> Below is the header info from ncdump and the resulting info coming from 
> gdalinfo. Can you use multi-dimensional coordinate variables in 
> conjunction with gdal?
> If so, can you advise what I need to do to make my netcdf file work with 
> gdal?

Aaron,

Unfortunately, the GDAL NetCDF driver does not currently support using
lat/lon arrays for georeferencing an image (what we call geolocation
arrays in GDAL).  This is a deficiency in the driver, though even if it
was supported there are still only a few GDAL tools that take advantage
of geolocation arrays.

If you can work out what the projected coordinate system is, and what the
proper geotransform (origin and pixel size) would apply for the file, you
could attach this to the image using something like a VRT file.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent



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