[Gdal-dev] Problem using gdal_translate on netcdf file

[Hernán De Angelis]

Your files are in Float32 format, try rescaling them to 8bit:
gdal_translate -ot Byte

2007/1/20, Chase, Andrew <achase at mbari.org>:
>
>  Hi All,
>
> I'm trying to convert a netcdf file to some an image format that I can use
> with imagemagick (tiff, jpg, png, anything will do). Unfortunately, I'm
> having some troubles getting the job done. When I try gdal_translate with
> any format other than Gtiff I get a completely black image. When I use the
> Gtiff format, I get a weird grayscale mutated version of my source file,
> with strange grainy vertical bands. When I open the netcdf file in OpenEV it
> looks perfectly normal, and I use the netcdf file for a lot of different
> data processing, so I feel confident that the data itself is good (if not
> the formatting of the data).
>
> I've placed a subsetted version of the translated image online to show
> what the resulting geotiff looks like, it's here:
>
> *http://www.mbari.org/staff/achase/vdm/hrbath.tif*<http://www.mbari.org/staff/achase/vdm/hrbath.tif>
> Maybe someone else has seen this same type of image problem?
>
> Here's the gdalinfo output:
>
> C:\workspace\vdm\resources\grids>gdalinfo NETCDF:"hrbath.nc":elevation
> Driver: netCDF/Network Common Data Format
> Size is 5001, 4001
> Coordinate System is `'
> Origin = (-125.000000000000000,38.000999999999998)
> Pixel Size = (0.000999800039992,-0.000999750062484)
> Metadata:
>   NC_GLOBAL#creationDate=01/19/2007
>   NC_GLOBAL#lastModified=01/19/2007
>   NC_GLOBAL#Conventions=CF-1.0
>   NC_GLOBAL#CreatedBy=VARS Data Mining Software - MBARI
>   NC_GLOBAL#title=DEM Grid from hrbath.asc
>   NC_GLOBAL#institution=MBARI
>   NC_GLOBAL#creator_name=Andrew Chase
>   NC_GLOBAL#keywords=dem bathymetry grid
>   elevation#positive=up
>   elevation#long_name=Elevation
>   elevation#missing_value=-9.999900e+004
>   elevation#units=meters
>   latitude#units=degrees_north (+N/-S)
>   longitude#units=degrees_east (+E/-W)
> Corner Coordinates:
> Upper Left  (-125.0000000,  38.0010000)
> Lower Left  (-125.0000000,  34.0010000)
> Upper Right (-120.0000000,  38.0010000)
> Lower Right (-120.0000000,  34.0010000)
> Center      (-122.5000000,  36.0010000)
> Band 1 Block=5001x1 Type=Float32, ColorInterp=Undefined
>   NoData Value=-99999
>   Metadata:
>     NETCDF_VARNAME=elevation
>
> ----------------------------------------------------------------------------------------------------------
>
> And here's the translation I'm trying:
>
> C:\workspace\vdm\resources\grids>gdal_translate -of GTiff -a_nodata -99999
> NETCD
> F:"hrbath.nc":elevation hrbath.tif
> Input file size is 5001, 4001
> 0...10...20...30...40...50...60...70...80...90...100 - done.
>
> ----------------------------------------------------------------------------------------------------------
>
> And the resulting gdalinfo output:
>
> C:\workspace\vdm\resources\grids>gdalinfo hrbath.tif
> Driver: GTiff/GeoTIFF
> Size is 5001, 4001
> Coordinate System is `'
> Origin = (-125.000000000000000,38.000999999999998)
> Pixel Size = (0.000999800039992,-0.000999750062484)
> Metadata:
>   NC_GLOBAL#creationDate=01/19/2007
>   NC_GLOBAL#lastModified=01/19/2007
>   NC_GLOBAL#Conventions=CF-1.0
>   NC_GLOBAL#CreatedBy=VARS Data Mining Software - MBARI
>   NC_GLOBAL#title=DEM Grid from hrbath.asc
>   NC_GLOBAL#institution=MBARI
>   NC_GLOBAL#creator_name=Andrew Chase
>   NC_GLOBAL#keywords=dem bathymetry grid
>   elevation#positive=up
>   elevation#long_name=Elevation
>   elevation#missing_value=-9.999900e+004
>   elevation#units=meters
>   latitude#units=degrees_north (+N/-S)
>   longitude#units=degrees_east (+E/-W)
> Corner Coordinates:
> Upper Left  (-125.0000000,  38.0010000)
> Lower Left  (-125.0000000,  34.0010000)
> Upper Right (-120.0000000,  38.0010000)
> Lower Right (-120.0000000,  34.0010000)
> Center      (-122.5000000,  36.0010000)
> Band 1 Block=5001x1 Type=Float32, ColorInterp=Gray
>   NoData Value=-99999
>   Metadata:
>     NETCDF_VARNAME=elevation
>
>
> Any ideas of what to try would be appreciated.
>
> -Andrew
>
> Andrew C. Chase
> Software Engineer
> Monterey Bay Aquarium Research Institute
>
> _______________________________________________
> Gdal-dev mailing list
> Gdal-dev at lists.maptools.org
> http://lists.maptools.org/mailman/listinfo/gdal-dev
>
>


-- 

Hernán De Angelis
Linux user # 397217
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/gdal-dev/attachments/20070120/8018ef78/attachment.html