[Ubuntu] [UbuntuGIS] #27: netcdf-4 unsupported in gdal builds

[UbuntuGIS]

#27: netcdf-4 unsupported in gdal builds
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 Reporter:  etourigny  |      Owner:  ubuntu@…              
     Type:  defect     |     Status:  new                   
Component:  GDAL       |   Severity:  important             
 Keywords:             |  
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 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 is used and it 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).

 ==> Simple fix is to add netcdf-bin as a dependency for gdal.


 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
 dpkg-buildpackage)
 {{{
 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.


 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 works out of the box :

 $ 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

-- 
Ticket URL: <http://trac.osgeo.org/ubuntugis/ticket/27>
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