Hi, I am new to GRASS but bought the book (3rd edition) and searched the mail archive before sending in this question. The issue is about reading a netCDF file: I got a "vertical mirror" of "upside down" effect (when I display the imported raster using d.rast) but when I use an old-fashioned technique (translating to GRASS ASCII, see below) it looks okay.
The netCDF file itself is fine when viewed using, e.g., Ferret (http://ferret.pmel.noaa.gov/Ferret/). The outputs of ncdump and gdalinfo are provided at the end of this mail. The best procedure would be to follow http://lists.osgeo.org/pipermail/grass-user/2010-September/057799.html and thus either use r.in.gdal directly: grass>r.in.gdal -o NETCDF:"r2.nc":xe out=xe2 (in a WGS84 LOCATION) or after a gdal_translate: grass>gdal_translate -a_srs EPSG:4326 NETCDF:"r2.nc":h0 h02.tiff grass>r.in.gdal h02.tiff out=h02 But when I view the resulting raster, h02, it is flipped "upside down" (as if the latitude was increasing "downward"). Thus so far I need to rely on a script which is actually a follow-up of this (old) thread: http://lists.osgeo.org/pipermail/grass-user/2002-December/008022.html I have attached the script I use to this mail, in case somebody finds it useful (you also need awk and nco); it is only an ersatz though, and I would like to know what I can do to import my netCDF file directly into GRASS (without a temporary GRASS ASCII file). Are there metadata I should add to the netCDF file to get r.in.gdal happy? Does r.in.gdal need a particular row order in the netCDF file (such as j index increasing southward)? That was a long one! Hope it was more or less clear. Nicolas PS the system I am working with: bash>uname -a Linux Herminet1 2.6.32-25-generic #45-Ubuntu SMP Sat Oct 16 19:48:22 UTC 2010 i686 GNU/Linux bash>gdalinfo --version GDAL 1.6.3, released 2009/11/19 bash>grass -v GRASS GIS 6.4.0RC5+39438 ##################### bash> ncdump -h r2.nc netcdf r2 { dimensions: longitude = 133 ; latitude = 64 ; time = UNLIMITED ; // (14 currently) variables: double longitude(longitude) ; longitude:units = "degrees_east" ; double latitude(latitude) ; latitude:units = "degrees_north" ; double time(time) ; time:units = "seconds since 1900-1-1" ; float h0(latitude, longitude) ; h0:units = "m" ; h0:missing_value = -999.f ; float xe(time, latitude, longitude) ; xe:units = "m" ; xe:missing_value = -999.f ; float u(time, latitude, longitude) ; u:units = "m/s" ; u:missing_value = -999.f ; float v(time, latitude, longitude) ; v:units = "m/s" ; v:missing_value = -999.f ; // global attributes: :Conventions = "COARDS" ; } #################### bash> gdalinfo r2.nc Driver: netCDF/Network Common Data Format Files: r2.nc Size is 512, 512 Coordinate System is `' Metadata: NC_GLOBAL#Conventions=COARDS Subdatasets: SUBDATASET_1_NAME=NETCDF:"r2.nc":h0 SUBDATASET_1_DESC=[64x133] h0 (32-bit floating-point) SUBDATASET_2_NAME=NETCDF:"r2.nc":xe SUBDATASET_2_DESC=[14x64x133] xe (32-bit floating-point) SUBDATASET_3_NAME=NETCDF:"r2.nc":u SUBDATASET_3_DESC=[14x64x133] u (32-bit floating-point) SUBDATASET_4_NAME=NETCDF:"r2.nc":v SUBDATASET_4_DESC=[14x64x133] v (32-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)
nc2grass.sh
Description: application/shellscript
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