[gdal-dev] gdalwarp has blank metadata

[Even Rouault]

On lundi 13 février 2017 21:32:02 CET Adam Dershowitz wrote:
> I have been using gdalwarp to convert a geotiff to NetCDF format.  The odd
> thing is that if the result is in feet, I get blank units in my output
> metadata units.  While if I go to meters, I get the correct units.
 
> So for example this works correctly:
> 
> 
> gdalwarp  -t_srs EPSG:3651 -of netCDF cea.tif cea_m.nc
> 
> and gdalinof shows data like this:
>   x#standard_name=projection_x_coordinate
>   x#units=m
>   y#long_name=y coordinate of projection
>   y#standard_name=projection_y_coordinate
>   y#units=m
> 
> 
> While this:
> gdalwarp  -t_srs EPSG:3652 -of netCDF cea.tif cea_ft.nc
> 
> Has this metadata:
>   x#standard_name=projection_x_coordinate
>   x#units=
>   y#long_name=y coordinate of projection
>   y#standard_name=projection_y_coordinate
>   y#units=
> 
> The reason that this is an issue is that I’m trying to view this data with a
> reader that is crashing due to the empty strings.  I have reported a bug
> there, and it is being addressed.
 But, it does seem like there is also an
> issue with gdalwarp generating these empty strings for netCDF files. 
> Shouldn’t these strings contain “feet”? I did try to use gdal_edit to try
> to change that, but didn’t have any luck for the netCDF file. 
> Any suggestions for how to fix these files?  And, how to work around this
> problem?

Adam, 

The netCDF driver didn't have support for US survey foot unit. I've added it per https://
trac.osgeo.org/gdal/changeset/37378

I used the "US_survey_foot" string accordingly with
http://mooring.ucsd.edu/software/matlab/mfiles/netcdf/udunits.dat , but I'd appreciate 
confirmation from netCDF experts lurking around.

As a workaround you could use ncdump / ncgen to edit the existing file.

Even


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