Hello, On 2020-11-17 at 10:06 -08, Ken Mankoff <[email protected]> wrote... > I've successfully worked in rotated pole coordinates (e.g., [1]) but > because I don't know what (x,y) coord contains the pole, I haven't > figured out how to adapt this to the rotated pole situation as in [1]. > Anyway, this isn't a rotated pole...
I was incorrect - this is a rotated pole coordinate system. When I run the following code on GRASS 7.4, I get the attached graphic. The key part here is that the rotated pole is at (lon,lat) = (-200,18). grass -c EPSG:4326 Gnorm # Import something into the normal location v.import input=~/data/Zwally_2012/sectors output=Z cat << EOF > ./Gnorm/PERMANENT/PROJ_INFO name: General Oblique Transformation datum: wgs84 towgs84: 0.000,0.000,0.000 proj: ob_tran o_proj: latlon ellps: wgs84 a: 6378137.0000000000 es: 0.0066943800 f: 298.2572235630 lat_0: 0.0000000000 lon_0: 180.0000000000 o_lat_p: 18.0 o_lon_p: -200.0 EOF # rotated_pole:grid_north_pole_latitude = 18. ; # rotated_pole:grid_north_pole_longitude = -200. cat << EOF > ./Gnorm/PERMANENT/PROJ_UNITS unit: degree units: degrees meters: .0174532925 EOF grass -e -c EPSG:4326 Grot grass ./Grot/PERMANENT v.proj location=Gnorm input=Z g.region vector=Z d.mon start=wx0 d.vect Z d.grid 1:0:0 The above code run in GRASS 7.4.0 on a clean Ubuntu 18.04 VM produces the attached graphic. However, when I run the exact same code in GRASS 7.8.4 it does not work. The reproject/rotate does not occur, and Greenland remains at 62-82 N, and 22-72 W. The contents of the "Gnorm" folders is appears identical. The md5sum of DEFAULT_WIND, MYNAME, PROJ_EPSG, PROJ_INFO, and PROJ_UNITS are all the same. I can do the work in GRASS 7.4 in a VM but I'd prefer to do it on the main development machine in the latest GRASS. Does anyone have any idea why this feature stopped working? Thanks, -k.
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