[Gdal-dev] gdalwarp and lcc irregularly spaced grids

[Stanley Glidden]

Hi,

Can Gdal re-project irregular lambert conformal grids stored as NetCDF 
files?


If possible I would like to use gdalwarp to project the NCEP North 
American Regional Reanalysis NetCDF files to Geographic.

This is what I tried:

gdalwarp -s_srs '+proj=lcc +ellps=WGS84 +lat_1=50dN +lon_0=107dW 
+x_0=5632642.22547 +y_0=4612545.65137 +k_0=0.99995696 +units=m +no_defs' -t_srs 
'+proj=longlat +ellps=GRS80 +datum=wgs84 +no_defs' NETCDF:"air.197901.nc":air 
test.tif

This is the error I get:

ERROR 1: Unable to compute a transformation between pixel/line
and georeferenced coordinates. There is no affine transformation and no GCPs

Is there missing required information in the NetCDF files, or is the problem 
simply that they are irregularly spaced grids?


Thanks.

Stanley
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The data files were downloaded from:

http://www.cdc.noaa.gov/cdc/data.narr.pressure.html


ftp://ftp.cdc.noaa.gov/Datasets/NARR/pressure/


Results of gdalinfo:

Driver: netCDF/Network Common Data Format
Size is 512, 512
Coordinate System is `'
Metadata:
   NC_GLOBAL#Conventions=CF-1.0
   NC_GLOBAL#title=Daily NARR
   NC_GLOBAL#history=created 2005/07 by Hoop (netCDF2.3)
   NC_GLOBAL#comments=Data is from North American Regional Reanalysis
(8x/day).  It consists of most variables interpolated to
pressure surfaces from model (sigma) surfaces.
   NC_GLOBAL#institution=National Centers for Environmental Prediction
   NC_GLOBAL#platform=Model
   NC_GLOBAL#references=http://wwwt.emc.ncep.noaa.gov/mmb/rreanl/index.html
http://www.cdc.noaa.gov/cdc/data.narr.html
Subdatasets:
   SUBDATASET_1_NAME=NETCDF:"/net/usr/spool/air.197901.nc":lat
   SUBDATASET_1_DESC=[277x349] latitude (32-bit floating-point)
   SUBDATASET_2_NAME=NETCDF:"/net/usr/spool/air.197901.nc":lon
   SUBDATASET_2_DESC=[277x349] longitude (32-bit floating-point)
   SUBDATASET_3_NAME=NETCDF:"/net/usr/spool/air.197901.nc":time_bnds
   SUBDATASET_3_DESC=[31x2] time_bnds (64-bit floating-point)
   SUBDATASET_4_NAME=NETCDF:"/net/usr/spool/air.197901.nc":air
   SUBDATASET_4_DESC=[31x29x277x349] air_temperature (8-bit integer)
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)


Information about the files:

The native model grid is converted to a Northern Lambert Conformal Conic 
grid which is what we archive. Corners of this grid are 12.2N;133.5W, 
54.5N; 152.9W, 57.3N; 49.4W ,14.3N;65.1W (essentially, North America). The 
grid resolution is 349x277 which is approximately 0.3 degrees (32km) 
resolution at the lowest latitude. A page describing the coverage along 
with information on reading the projection is available.

More info:
http://www.cdc.noaa.gov/NARR/format.html