[Ubuntu] problem with netcdf-4 files with gdal build

[Etienne Tourigny]

I have added a bug report for this problem - simple solution: add
netcdf-bin as a dependency for building gdal.

http://trac.osgeo.org/ubuntugis/ticket/27

thanks
Etienne

On Wed, Nov 14, 2012 at 10:44 AM, Etienne Tourigny
<etourigny.dev at gmail.com> wrote:
> Hi,
>
> The ubuntugis-unstable builds of gdal have a problem with netcdf-4
> files (which use hdf5 storage).
>
> The consequence is that netcdf-4 files are not supported in apps that
> use gdal (like qgis), because the hdf5 driver does not read dimension
> information of netcdf-4 files.
>
> Long story short - proper detection of netcdf-4 support in gdal netcdf
> driver requires nc-config which is in netcdf-bin package - although it
> should be in libnetcdf-dev (these are built by ubuntu).
>
> Could the packagers add netcdf-bin as a dependency for gdal builds?
>
>
> Long story:
>
> netcdf-4 files use hdf5 format, but the netcdf driver should try to
> open them first. If the file has nc/nc2/nc4/cdf suffix, the netcdf
> driver tries to open the file, and if it fails then the hdf5 driver is
> used.
> Normally the netcdf driver is loaded before the hdf5 driver.
>
> This works well on my builds, but it doesn't work with the ubuntugis builds.
>
> I have traced the source of the problem to the build log at
> https://launchpadlibrarian.net/122450487/buildlog_ubuntu-oneiric-amd64.gdal_1.9.2-2~oneiric6_BUILDING.txt.gz
>
> ===
> checking for nc-config... no
>         did not find nc-config, some features may be missing
>         use --with-netcdf=/path/to/netcdf or add nc-config to PATH
> checking for nc_open in -lnetcdf... yes
> ===
>
> Proper output (which I get by building the same package from source using
> ===
> checking for nc-config... /usr/bin/nc-config
> checking libnetcdf compiler and linker flags with nc-config...
>  got version="netCDF 4.1.1", prefix="/usr",
>  libs="-L/usr/lib -lnetcdf", includedir="/usr/include"
> checking for nc_open in -lnetcdf... yes
> checking for netcdf-4 (and HDF5) support in libnetcdf... yes
> ===
>
> The source of this error is that libnetcdf used for the build lacks nc-config.
>
>
> Thanks,
> Etienne
>
> P.S.
>
> You can try with the sample datasets in the gdal autotest :
> autotest/gdrivers/data/trmm-nc4.nc
>
> with gdal-1.9.2-2 from ubuntugis-unstable (oneiric):
>
>
> $ gdalinfo /data/src/gdal/svn/branches/1.9/autotest/gdrivers/data/trmm-nc4.nc
> Driver: HDF5Image/HDF5 Dataset
> Files: /data/src/gdal/svn/branches/1.9/autotest/gdrivers/data/trmm-nc4.nc
> Size is 40, 40
>
> Forcing the use of the netcdf driver works (because libnetcdf does has
> hdf5 support):
>
> $ gdalinfo NETCDF:/data/src/gdal/svn/branches/1.9/autotest/gdrivers/data/trmm-nc4.nc
> Warning 1: NetCDF driver detected file type=5, but libnetcdf detected type=3
> Driver: netCDF/Network Common Data Format
> Files: none associated
> Size is 40, 40
>
>
> with a custom build :
>
> $ gdalinfo  NETCDF:/data/src/gdal/svn/branches/1.9/autotest/gdrivers/data/trmm-nc4.nc
> Driver: netCDF/Network Common Data Format
> Files: none associated
> Size is 40, 40