[gdal-dev] Re: gdal_rasterize with a NetCDF file?

Even Rouault even.rouault at mines-paris.org
Mon Sep 21 15:02:46 EDT 2009 

Selon Scott Lewis <scott.lewis at nsidc.org>:

You've got the main point, but the meaning of '+' is a bit more subtle. The '+'
indicates in fact support for the Create() method. Some drivers support updating
existing datasets (like DTED for example), or CreateCopy() (translating entire
existing dataset to the new format) but not the Create() method itself.

I realize that many drivers are missing code to error out with proper message if
they are requested to open the dataset in update mode, but they don't support
it. It's done properly in some (GIF, JPEG, PNG, ...), but not in netCDF, ....
I'll try to improve that.

> Ah, thanks.  I must have missed that.  Looks like I'll have to find
> another way to accomplish what I'm trying to do then!
>
> Thanks for your help!
>
> Scott
>
> Hermann Peifer wrote:
> > The driver doesn't support updating netCDF files. gdalinfo --formats says:
> >
> >  GTiff (rw+): GeoTIFF
> >  (...)
> >  netCDF (rw): Network Common Data Format
> >
> > The "+" indicates update support, which is obviously missing for netCDF
> > format.
> >
> > Hermann
> >
> >
> > -------- Original Message  --------
> > Subject: Re:gdal_rasterize with a NetCDF file?
> > From: Scott Lewis <scott.lewis at nsidc.org>
> > To: Date: 21/09/2009 20:37
> >
> >> Evan,
> >>
> >> Thanks, that seems to be getting me in the right direction: I'm no
> >> longer getting the segfault error, or "ERROR 5" at all.
> >>
> >> However, now it's giving me a different error.  The first line has the:
> >> 0...10...20...30...40...50...60...70...80...90...100 - done.
> >> message, like I would expect from when I do this with GeoTIFF files.
> >> But following that I am getting a whole bunch of this error, repeated
> >> many times:
> >>
> >> ERROR 6: WriteBlock() not supported for this dataset.
> >>
> >>
> >> Doing a search online, I'm getting the impression that this might mean
> >> that gdal_rasterize doesn't support writing to a NetCDF file?  Is this
> >> correct, or does the problem lie elsewhere with my calling of the
> >> utility.
> >>
> >> Here's the command line I'm using now:
> >>
> >> /usr/local/FWTools-2.0.6/bin_safe/gdal_rasterize -i -burn 0 -l
> >> "OGRGeoJSON" dummy.json
> >> 'NETCDF:"Albedo.nc":Albedo_with_1400_Local_Time_of_Measurement'
> >>
> >>
> >> Thanks again for the help!
> >>
> >> Scott
> >>
> >>
> >> Even Rouault wrote:
> >>> Selon Scott Lewis <scott.lewis at nsidc.org>:
> >>>
> >>> Scott,
> >>>
> >>> Anytime you want to access to a subdataset with a gdal utility, you
> >>> must use the
> >>> value of the relevant SUBDATASET_xxx_NAME metadata item, in that
> >>> instance
> >>> 'NETCDF:"Albedo.nc":Albedo_with_1400_Local_Time_of_Measurement'
> >>>
> >>> The segmentation fault however wasn't expected, so I commited fixes
> >>> per ticket
> >>> http://trac.osgeo.org/gdal/ticket/3146 to error out more nicely.
> >>>
> >>> Best regards
> >>>
> >>>> Hi,
> >>>>
> >>>> I'm still fairly new at using GDAL, but I am having trouble burning a
> >>>> vector image onto a NetCDF file.  I've had success with using
> >>>> gdal_rasterize to burn a vector onto a GeoTIFF file, but when I try to
> >>>> burn the same vector onto a NetCDF file, I get an error.
> >>>>
> >>>> Based on the error, I'm suspecting it's because it doesn't know how to
> >>>> find the right "band" in the NetCDF File (I want the
> >>>> "Albedo_with_1400_Local_Time_of_Measurement" subdataset), but although
> >>>> I've looked at the documentation, I'm not sure how to specify this to
> >>>> gdal_rasterize.
> >>>>
> >>>> Any help would be much appreciated!  Below is the info.
> >>>>
> >>>>
> >>>>
> >>>> Here is the command I am trying to run:
> >>>>
> >>>> /usr/local/FWTools-2.0.6/bin_safe/gdal_rasterize -i -burn 0 -l
> >>>> "OGRGeoJSON" dummy.json Albedo.nc
> >>>>
> >>>>
> >>>> And the error I get:
> >>>>
> >>>> ERROR 5: GDALDataset::GetRasterBand(1) - Illegal band #
> >>>>
> >>>> /usr/local/FWTools-2.0.6/bin_safe/gdal_rasterize: line 9: 26950
> >>>> Segmentation fault      $FWTOOLS_HOME/bin/`basename $TARGET` "$@"
> >>>>
> >>>>
> >>>>
> >>>> Here is the gdalinfo for Albedo.nc:
> >>>>
> >>>> Driver: netCDF/Network Common Data Format
> >>>> Files: Albedo.nc
> >>>> Size is 512, 512
> >>>> Coordinate System is `'
> >>>> Metadata:
> >>>>   NC_GLOBAL#Conventions=CF-1.4
> >>>>   NC_GLOBAL#institution=National Snow & Ice Data Center, Boulder, CO
> >>>>   NC_GLOBAL#title=AVHRR Polar Pathfinder Twice-Daily 5 km EASE-Grid
> >>>> Composites Albedo
> >>>>   NC_GLOBAL#source=See the title and references for this information
> >>>>   NC_GLOBAL#comment=Not set at this time
> >>>>   NC_GLOBAL#references=Documentation available at:
> >>>> http://nsidc.org/data/docs/daac/nsidc0066_avhrr_5km.gd.html
> >>>>   NC_GLOBAL#history=Mon, 21 Sep 2009 09:31:24: File created.
> >>>> Subdatasets:
> >>>>
> >>>>
> >>>
>
SUBDATASET_1_NAME=NETCDF:"Albedo.nc":Albedo_with_1400_Local_Time_of_Measurement
> >>>
> >>>>   SUBDATASET_1_DESC=[1x244x242]
> >>>> Albedo_with_1400_Local_Time_of_Measurement (8-bit integer)
> >>>>   SUBDATASET_2_NAME=NETCDF:"Albedo.nc":latitude
> >>>>   SUBDATASET_2_DESC=[244x242] latitude (64-bit floating-point)
> >>>>   SUBDATASET_3_NAME=NETCDF:"Albedo.nc":longitude
> >>>>   SUBDATASET_3_DESC=[244x242] longitude (64-bit floating-point)
> >>>> Corner Coordinates:
> >>>> Upper Left  (    0.0,    0.0)
> >>>> Lower Left  (    0.0,  512.0)
> >>>> Upper Right (  512.0,    0.0)
> >>>> Lower Right (  512.0,  512.0)
> >>>> Center      (  256.0,  256.0)
> >>>>
> >>>>
> >>>> And for completeness, the dummy.json file (it's basically a triangle):
> >>>>
> >>>> {
> >>>>     "type": "FeatureCollection",
> >>>>     "features": [{
> >>>>         "type": "Feature",
> >>>>         "properties": { "BASIN_ID": 1.000000, "AREA_SQKM":
> >>>> 1739.016470 },
> >>>>         "geometry": {
> >>>>             "type": "Polygon",
> >>>>             "coordinates": [ [
> >>>>                 [ -2000000, -2500000 ],
> >>>>                 [ -2500000, -1400000 ],
> >>>>                 [ -1500000, -1400000 ],
> >>>>                 [ -2000000, -2500000 ]
> >>>>             ] ]
> >>>>         }
> >>>>     }]
> >>>> }
> >>>>
> >>>>
> >>>>
> >>>> Thanks!
> >>>>
> >>>> Scott Lewis
> >>>> National Snow & Ice Data Center
> >>>> _______________________________________________
> >>>> gdal-dev mailing list
> >>>> gdal-dev at lists.osgeo.org
> >>>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
> >>>>
> >>>
>

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