On 18/11/20 15:01, Ken Mankoff wrote:
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?
Maybe because of changes linked to proj6 support ? Markus Metz will know.
Moritz
Moritz
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