The Z, Y', X'' rotation scheme, intrinsic or extrinsic, sounds like an
application of Euler (sounds like "Oiler") angles [1,2].
Tom Kunicki
Center for Integrated Data Analytics
U.S. Geological Survey
8505 Research Way
Middleton, WI 53562
[1] http://en.wikipedia.org/wiki/Euler_angles
[2] http:/
Dear all
There is one model in the CMIP5 database (inmcm4) that has a rotated-pole
grid (for the ocean) which uses a non-zero north_pole_grid_longitude. This
is the first time I've encountered the use of that parameter, so I'm glad
that we included it in the CF definition! It was me, I think, who
Hi John,
grid_north_pole_latitude = -1 * longitudeOfSouthernPoleInDegrees
is ok
The normalize function is just used because grib is 0-360, while proj is
-180 to 180. But you need to flip longitude when going from north to south:
grid_north_pole_longitude = norm180(longitudeOfSouthernPoleIn
Hi Seth:
Thanks for the description, its really helpful.
Im just wondering how we document this in the CF convention, so that
implementers have something to check against. Is there a "reference
implementation" we can use ?
John
On 3/6/2013 1:17 PM, Seth McGinnis wrote:
So there are an infi
Hi Burkhardt:
Of course we cant change the existing conventions as there are files
that already use it. But we need to document it so that we know when we
are doing it right.
Im cleaning up my code and noticed that i have two implementations, one
for grib and one for CF. So Id like to merge
So there are an infinite number of ways to decompose a 3-D orientation into
three orthogonal rotations. Specifying the projection in terms of the final
location of the north pole and an optional rotation around that point means
that CF is actually agnostic about exactly how you get there.
That sa
John,
the rotated pole definition was requested by me in 2002 (see the thread
"projections/default cell_methods"). In this thread the present description was
chosen.
Please note: the rotated pole grid mapping is NOT a PROJECTION! it is a
TRANSFORMATION (therefore the GRIB description
Hello,
It is a bit of mess! As I understand it, the full rotation described
is a sequence of rotations about three different axes:
Z = 90S - 90N
Y' = 90W' - 90E'
X" = 0E" - 180E"
where it is understood that the definitions of the N-S and W-E axes
change after each rotation (hence the p
Hi Heiko:
So
grid_north_pole_longitude =
normalizeLongitude180(longitudeOfSouthernPoleInDegrees)
grid_north_pole_latitude = -1 * longitudeOfSouthernPoleInDegrees
?
where does one find documentation on proj4's ob_tran routine?
thanks,
John
On 3/6/2013 8:03 AM, Heiko Klein wrote:
Hi John,
Hi John,
all our models use rotated_latitute_longitude. And we have a consistent
way of translating it between grib, proj and netcdf-java, i.e. publicly
available at:
http://thredds.met.no/thredds/catalog/metno/proff4km/default/catalog.html
grid_mapping_name: rotated_latitude_longitude
grid_
The "Rotated Pole" projection here:
http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/cf-conventions.html#appendix-grid-mappings
Rotated pole
grid_mapping_name = rotated_latitude_longitude
Map parameters:
*
grid_north_pole_latitude
*
grid_north_pol
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