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]
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
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
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
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
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 =
