[GRASS-user] trouble with netCDF input arguments for r.in.gdal
Jennifer Boehnert
boehnert at ucar.edu
Mon Oct 1 11:22:00 PDT 2012
Hi Kirk,
in your r.in.gdal syntax the time_bnds is the variable you want to
read. My guess would be the variable you want to read is pet.
I would suggestion executing the following commands to read your file
metadata before running the r.in.gdal.
/gdalinfo D:\data\projects\courses2012\IAI\data\B1_tas.nc
/
This will give you the variable names in your dataset. In your case I
see PET
Then to find the dimensions on the variable of interest execute The
syntax is your netCDF name : variable name
/gdalinfo NETCDF:D:\data\projects\courses2012\IAI\data\A2_tas.nc:tasC /
In my example the netCDF name is A2_tas.nc an the variable I want is
tasC (temperature in degrees celsius). My data has 10 temporal dimensions.
You should put <netCDF Name>:PET
Now that I know this I run the r.in.gdal
/r.in.gdal -o -e input=NETCDF:
D:\data\projects\courses2012\IAI\data\A2_tas.nc:tasC output=SRESA2_tas/
In this example I am bringing in all times if you want specify just 1
time you can do so by using the BAND number.
Jennifer
On 10/1/2012 12:02 PM, Kirk Wythers wrote:
> I am trying to read some netCDF data (from the CRU climate database)
> into grass. I am looking at the netcdf wiki page and having a little
> trouble translating the instructions there to the output I am getting
> from "gdalinfo". Here is the
>
> If I am trying to use syntax that looks something like:
> r.in.gdal input=NETCDF:"sst.nc":time_bnds output=sst
> I am getting the following error:
>
> ERROR 4:
> `NETCDF:~/Downloads/cru_ts_3_10.1901.2009.pet.dat.nc:time_bnds' does
> not exist in the file system,
> and is not recognised as a supported dataset name.
>
> In my case, the PATH_TO_FILE is
>
> "~/Downloads/cru_ts_3_10.1901.2009.pet.dat.nc"
>
> However, I can't tell what to use in the place of ":time_bnds". Any
> ideas from the pasted text below of what my input argument should look
> like?
>
> Thanks in advance,
>
> Kirk
>
>
> Here is output I am looking at from gdalinfo:
>
> GRASS 6.4.1 (globe_30min):~ > gdalinfo
> ~/Downloads/cru_ts_3_10.1901.2009.pet.dat.nc
> ERROR 1: GDAL/GRASS57 driver was compiled against GDAL 1.8 but current
> library version is 1.9
>
> ERROR 1: GDAL/GRASS57 driver was compiled against GDAL 1.8 but current
> library version is 1.9
>
> Driver: netCDF/Network Common Data Format
> Files:
> /Network/Servers/truffula.fr.umn.edu/Volumes/disk1/home1/kirkw/Downloads/cru_ts_3_10.1901.2009.pet.dat.nc
> <http://truffula.fr.umn.edu/Volumes/disk1/home1/kirkw/Downloads/cru_ts_3_10.1901.2009.pet.dat.nc>
> Size is 720, 360
> Coordinate System is `'
> Origin = (-180.000000000000000,90.000000000000000)
> Pixel Size = (0.500000000000000,-0.500000000000000)
> Metadata:
> lat#long_name=latitude
> lat#units=degrees_north
> lon#long_name=longitude
> lon#units=degrees_east
> NC_GLOBAL#comment=Data restrictions: for academic research use
> only.Contact BADC for details
> NC_GLOBAL#contact=BADC <badc at rl.ac.uk <mailto:badc at rl.ac.uk>>
> NC_GLOBAL#Conventions=CF-1.4
> NC_GLOBAL#history=Wed Feb 2 03:32:36 GMT 2011 : User badc : Program
> makegridsauto.for called by update.for
> NC_GLOBAL#institution=Data held at British Atmospheric Data Centre,
> RAL, UK.
> NC_GLOBAL#references=Information on the data is available at
> http://badc.nerc.ac.uk/data/cru/
> NC_GLOBAL#source=Run ID = 1102011219
> Data generated by BADC from:
> tmp.1009221824.dtb
> dtr.1009221824.dtb
> vap.1009221824.dtb
> cld.1009221824.dtb
> NC_GLOBAL#title=CRU TS 3.10 Potential Evapotranspiration
> pet#_FillValue=9.969209968386869e+36
> pet#correlation_decay_distance=-999
> pet#long_name=potential evapotranspiration
> pet#missing_value=9.969209968386869e+36
> pet#units=mm
> time#calendar=gregorian
> time#long_name=time
> time#units=days since 1900-1-1
> Corner Coordinates:
> Upper Left (-180.0000000, 90.0000000)
> Lower Left (-180.0000000, -90.0000000)
> Upper Right ( 180.0000000, 90.0000000)
> Lower Right ( 180.0000000, -90.0000000)
> Center ( 0.0000000, 0.0000000)
> Band 1 Block=720x1 Type=Float64, ColorInterp=Undefined
> NoData Value=9.96920996838686905e+36
> Metadata:
> _FillValue=9.969209968386869e+36
> correlation_decay_distance=-999
> long_name=potential evapotranspiration
> missing_value=9.969209968386869e+36
> NETCDF_DIMENSION_time=380
> NETCDF_time_units=days since 1900-1-1
> NETCDF_VARNAME=pet
> units=mm
> Band 2 Block=720x1 Type=Float64, ColorInterp=Undefined
> NoData Value=9.96920996838686905e+36
> Metadata:
> _FillValue=9.969209968386869e+36
> correlation_decay_distance=-999
> long_name=potential evapotranspiration
> missing_value=9.969209968386869e+36
> NETCDF_DIMENSION_time=410
> NETCDF_time_units=days since 1900-1-1
> NETCDF_VARNAME=pet
> units=mm
> .
> .
> .
> .
> Band 1308 Block=720x1 Type=Float64, ColorInterp=Undefined
> NoData Value=9.96920996838686905e+36
> Metadata:
> _FillValue=9.969209968386869e+36
> correlation_decay_distance=-999
> long_name=potential evapotranspiration
> missing_value=9.969209968386869e+36
> NETCDF_DIMENSION_time=40161
> NETCDF_time_units=days since 1900-1-1
> NETCDF_VARNAME=pet
> units=mm
>
>
>
>
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