True, we don't care where the needle points - we need polar north, it's
entirely dependent on longitude, and in our usual case, stere centred on
south pole, a simple special case.
Cheers, Mike
On Tue, 29 Jun 2021, 01:06 Andrew C Aitchison,
wrote:
> On Fri, 25 Jun 2021, Michael Sumner wrote:
>
>
On Fri, 25 Jun 2021, Michael Sumner wrote:
Hello, we're using `gdaldem aspect` on polar grid products and we need to
convert the grid-oriented directions to compass oriented ones,
location-specific directions, where "compass north" is dependent on
longitude.
I am curious; in the terminology of
The proj_factors(...) function, which a.o. returns the meridian convergence
in the PJ_FACTORS typedef, may be useful in this work.
Den fre. 25. jun. 2021 kl. 12.26 skrev Even Rouault <
even.roua...@spatialys.com>:
> Michael,
>
> A general solution would have more appeal, although I suspect it wil
Michael,
A general solution would have more appeal, although I suspect it will be
a bit more computation intensive as you'll probably have to transform to
invoke PROJ multiple times per grid point to compute the direction to
the North
Even
Le 25/06/2021 à 06:29, Michael Sumner a écrit :
Hel
Hello, we're using `gdaldem aspect` on polar grid products and we need to
convert the grid-oriented directions to compass oriented ones,
location-specific directions, where "compass north" is dependent on
longitude.
It's easy but inefficient for us to do this after running gdal dem for our
polar g
