[gdal-dev] Fwd: WRF NetCDF import

Etienne Tourigny etourigny.dev at gmail.com
Mon Nov 25 10:23:32 PST 2013 

Forwarding to the list and others...

---------- Forwarded message ----------
From: Roger Veciana i Rovira <rveciana at gmail.com>
Date: Mon, Nov 25, 2013 at 9:35 AM
Subject: Re: [gdal-dev] WRF NetCDF import
To: Etienne Tourigny <etourigny.dev at gmail.com>


As Etienne told you, the geotransform and projection from your files is not
in the format that GDAL can understand.
I wrote a script that reads the projection and calculates the geotransform
to save it in a GeoTIFF file:

http://geoexamples.blogspot.com.es/2013/09/reading-wrf-netcdf-files-with-gdal.html

The script also interpolates the WRF sigma levels to the desired pressure
level, so you will have to look for the functions that you need.

Anyway, the solution is quite complicated, and using cdo, nco or other
tools (I use ARWPost) may be easier.

Roger


2013/11/24 Etienne Tourigny <etourigny.dev at gmail.com>

> The "georeferencing info" you refer to is non-standard, and GDAL cannot
> use that. It (and presumably the grass provider, although I don't know) use
> the CF standard for encoding lat/lon information. what is the output of
> gdalinfo NETCDF:test_full.nc:HGT
>
> I don't know how the grass provider deals with subdatasets, but if you
> open the file in qgis (using the gdal provider, it will sllow you to select
> the subdataset you want).
>
> You could also extract the variable with another tool like cdo or nco.
>
> Etienne
>
>
>
> On Sat, Nov 23, 2013 at 7:47 PM, Lee Eddington <lee.w.eddington at gmail.com>wrote:
>
>> I'm trying to use r.in.gdal in GRASS GIS to import Weather Research &
>> Forecasting (WRF) model NetCDF output.  There have been some tips provided
>> by the GRASS users list, but none have worked for me.  I can import the
>> data as a simple x,y array with no georeferencing, but information about
>> georeferencing is in the file as other programs read, georeference and
>> display the file correctly.
>>
>> gdalinfo produces the following:
>>
>> lees-mbp:full Lee$ gdalinfo test_full.nc
>> Warning 1: No UNIDATA NC_GLOBAL:Conventions attribute
>>  Driver: netCDF/Network Common Data Format
>> Files: test_full.nc
>> Size is 512, 512
>> Coordinate System is `'
>> Metadata:
>>   NC_GLOBAL#BL_PBL_PHYSICS=1
>>   NC_GLOBAL#BOTTOM-TOP_GRID_DIMENSION=28
>>   NC_GLOBAL#BOTTOM-TOP_PATCH_END_STAG=28
>>   NC_GLOBAL#BOTTOM-TOP_PATCH_END_UNSTAG=27
>>   NC_GLOBAL#BOTTOM-TOP_PATCH_START_STAG=1
>>   NC_GLOBAL#BOTTOM-TOP_PATCH_START_UNSTAG=1
>>   NC_GLOBAL#BUCKET_J=-1
>>   NC_GLOBAL#BUCKET_MM=-1
>>   NC_GLOBAL#CEN_LAT=-8.4095154
>>   NC_GLOBAL#CEN_LON=115.02
>>   NC_GLOBAL#CU_PHYSICS=0
>>   NC_GLOBAL#DAMP_OPT=0
>>   NC_GLOBAL#DAMPCOEF=0.2
>>   NC_GLOBAL#DFI_OPT=0
>>   NC_GLOBAL#DIFF_6TH_FACTOR=0.12
>>   NC_GLOBAL#DIFF_6TH_OPT=0
>>   NC_GLOBAL#DIFF_OPT=1
>>   NC_GLOBAL#DT=16.666666
>>   NC_GLOBAL#DX=3000
>>   NC_GLOBAL#DY=3000
>>   NC_GLOBAL#FEEDBACK=0
>>   NC_GLOBAL#GFDDA_END_H=0
>>   NC_GLOBAL#GFDDA_INTERVAL_M=0
>>   NC_GLOBAL#GMT=12
>>   NC_GLOBAL#GRID_FDDA=0
>>   NC_GLOBAL#GRID_ID=3
>>   NC_GLOBAL#GRID_SFDDA=0
>>   NC_GLOBAL#GRIDTYPE=C
>>   NC_GLOBAL#HYPSOMETRIC_OPT=2
>>   NC_GLOBAL#I_PARENT_START=34
>>   NC_GLOBAL#ISFTCFLX=0
>>   NC_GLOBAL#ISHALLOW=0
>>   NC_GLOBAL#ISICE=24
>>   NC_GLOBAL#ISLAKE=-1
>>   NC_GLOBAL#ISOILWATER=14
>>   NC_GLOBAL#ISURBAN=1
>>   NC_GLOBAL#ISWATER=16
>>   NC_GLOBAL#J_PARENT_START=34
>>   NC_GLOBAL#JULDAY=324
>>   NC_GLOBAL#JULYR=2013
>>   NC_GLOBAL#KHDIF=0
>>   NC_GLOBAL#KM_OPT=4
>>   NC_GLOBAL#KVDIF=0
>>   NC_GLOBAL#MAP_PROJ=3
>>   NC_GLOBAL#MFSHCONV=0
>>   NC_GLOBAL#MMINLU=USGS
>>   NC_GLOBAL#MOAD_CEN_LAT=-8.4095078
>>   NC_GLOBAL#MOIST_ADV_OPT=1
>>   NC_GLOBAL#MP_PHYSICS=3
>>   NC_GLOBAL#NUM_LAND_CAT=24
>>   NC_GLOBAL#OBS_NUDGE_OPT=0
>>   NC_GLOBAL#OMLCALL=0
>>   NC_GLOBAL#PARENT_GRID_RATIO=3
>>   NC_GLOBAL#PARENT_ID=2
>>   NC_GLOBAL#POLE_LAT=90
>>   NC_GLOBAL#POLE_LON=0
>>   NC_GLOBAL#PREC_ACC_DT=0
>>   NC_GLOBAL#RA_LW_PHYSICS=1
>>   NC_GLOBAL#RA_SW_PHYSICS=1
>>   NC_GLOBAL#SCALAR_ADV_OPT=1
>>   NC_GLOBAL#SF_SFCLAY_PHYSICS=1
>>   NC_GLOBAL#SF_SURFACE_PHYSICS=2
>>   NC_GLOBAL#SF_URBAN_PHYSICS=0
>>   NC_GLOBAL#SGFDDA_END_H=0
>>   NC_GLOBAL#SGFDDA_INTERVAL_M=0
>>   NC_GLOBAL#SHCU_PHYSICS=0
>>   NC_GLOBAL#SIMULATION_START_DATE=2013-11-20_12:00:00
>>   NC_GLOBAL#SMOOTH_OPTION=0
>>   NC_GLOBAL#SOUTH-NORTH_GRID_DIMENSION=154
>>   NC_GLOBAL#SOUTH-NORTH_PATCH_END_STAG=154
>>   NC_GLOBAL#SOUTH-NORTH_PATCH_END_UNSTAG=153
>>   NC_GLOBAL#SOUTH-NORTH_PATCH_START_STAG=1
>>   NC_GLOBAL#SOUTH-NORTH_PATCH_START_UNSTAG=1
>>   NC_GLOBAL#SST_UPDATE=0
>>   NC_GLOBAL#STAND_LON=115.02
>>   NC_GLOBAL#START_DATE=2013-11-20_12:00:00
>>   NC_GLOBAL#SURFACE_INPUT_SOURCE=1
>>   NC_GLOBAL#SWRAD_SCAT=1
>>   NC_GLOBAL#TITLE= OUTPUT FROM WRF V3.4 MODEL
>>   NC_GLOBAL#TKE_ADV_OPT=1
>>   NC_GLOBAL#TRUELAT1=-8.4095001
>>   NC_GLOBAL#TRUELAT2=0
>>   NC_GLOBAL#W_DAMPING=0
>>   NC_GLOBAL#WEST-EAST_GRID_DIMENSION=199
>>   NC_GLOBAL#WEST-EAST_PATCH_END_STAG=199
>>   NC_GLOBAL#WEST-EAST_PATCH_END_UNSTAG=198
>>   NC_GLOBAL#WEST-EAST_PATCH_START_STAG=1
>>   NC_GLOBAL#WEST-EAST_PATCH_START_UNSTAG=1
>> Subdatasets:
>>   SUBDATASET_1_NAME=NETCDF:"test_full.nc":Times
>>   SUBDATASET_1_DESC=[1x19] Times (8-bit character)
>>   SUBDATASET_2_NAME=NETCDF:"test_full.nc":LU_INDEX
>>   SUBDATASET_2_DESC=[1x153x198] LU_INDEX (32-bit floating-point)
>>
>> (more SUBDATASETs)
>>
>>   SUBDATASET_106_NAME=NETCDF:"test_full.nc":LANDMASK
>>   SUBDATASET_106_DESC=[1x153x198] LANDMASK (32-bit floating-point)
>>   SUBDATASET_107_NAME=NETCDF:"test_full.nc":SST
>>   SUBDATASET_107_DESC=[1x153x198] SST (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)
>>
>> My first question is why am I getting the following warning?:
>>
>> Warning 1: No UNIDATA NC_GLOBAL:Conventions attribute
>>
>> Next, I see what appears is georeferencing info in the following lines:
>>
>>   NC_GLOBAL#CEN_LAT=-8.4095154
>>   NC_GLOBAL#CEN_LON=115.02
>>   NC_GLOBAL#MAP_PROJ=3 (Mercator)
>>   NC_GLOBAL#MOAD_CEN_LAT=-8.4095078
>>    NC_GLOBAL#STAND_LON=115.02
>>   NC_GLOBAL#TRUELAT1=-8.4095001
>>
>> but obviously this is not being interpreted or used.
>>
>> Trying to use gdalwarp:
>>
>> lees-mbp:full Lee$ gdalwarp NETCDF:test_full.nc:HGT test_full_HGT.tif
>> Warning 1: No UNIDATA NC_GLOBAL:Conventions attribute
>> ERROR 1: Unable to compute a transformation between pixel/line
>> and georeferenced coordinates for NETCDF:test_full.nc:HGT.
>> There is no affine transformation and no GCPs.
>>
>> Can anyone explain what I need to do?
>>
>> Thanks,
>> Lee
>>
>>
>> _______________________________________________
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>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>>
>
>
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