[gdal-dev] gdalwarp has blank metadata

Adam Dershowitz adershowitz at exponent.com
Mon Feb 13 17:58:16 PST 2017

Thanks much for both the fix and the work around. I'll look into ncdump.


-----Original Message-----
From: Even Rouault [even.rouault at spatialys.com<mailto:even.rouault at spatialys.com>]
Sent: Monday, February 13, 2017 03:04 PM Pacific Standard Time
To: gdal-dev at lists.osgeo.org
Cc: Adam Dershowitz
Subject: Re: [gdal-dev] gdalwarp has blank metadata

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?


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.



Spatialys - Geospatial professional services

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