[GRASS-user] seeking advice on importing "unprojected" data

[Ken Mankoff]

Hi GRASS list,

I'm trying to compare two data sets and need to import them into the same location. One is a GeoTIFF in WGS84 lon,lat coordinates. When I create a new GRASS location using "-c file.tif" everything appears to work, and

$ g.region -p
projection: 99 (unnamed)
zone:       0
datum:      wgs84
ellipsoid:  wgs84
etc...

And from gdalinfo:

Coordinate System is:
PROJCS["unnamed",
    GEOGCS["WGS 84",
        DATUM["WGS_1984",
            SPHEROID["WGS 84",6378137,298.257223563,
                AUTHORITY["EPSG","7030"]],
            AUTHORITY["EPSG","6326"]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","4326"]],
    PROJECTION["Polar_Stereographic"],
    PARAMETER["latitude_of_origin",70],
    PARAMETER["central_meridian",-45],
    PARAMETER["scale_factor",1],
    PARAMETER["false_easting",1],
    PARAMETER["false_northing",1],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (107900.000000000000000,-655550.000000000000000)
Pixel Size = (30.000000000000000,-30.000000000000000)


I have a second data set that I would like to co-locate with this one. That data comes in a NetCDF file but the projection is a custom rotated-pole projection. I have three variables in the NetCDF file: lon, lat, and the data.

What is the best method to convert on data set to the other? My first approach might be to convert the NetCDF to lon,lat,data ASCII file, import as points with m.proj, then convert to raster. I'm wondering if this is what the experts on this list would do. Note that I have one TIF, and 50,000 NetCDF time steps, so it may be more efficient to convert the TIF to the custom NetCDF projection, but it is not a requirement.

Thanks for any advice you may have,

  -k.