[OSRS-PROJ] Roussilhe Oblique Stereographic

Gerald Evenden gerald.evenden at verizon.net
Mon Mar 15 14:45:24 EST 2004

Again, I want to make one point *perfectly* clear: there is no Roussilhe
projection of any kind in *any* version of PROJ.

I am working on that issue now and I will hopefully come up with
two versions: one that is probably what Roussilhe first designed and
a second that seems to be used by the Poles for their grid systems.

The *only* stereographic projection in libproj4 (and earlier versions) 
Snyder's which is basically a Gauss conversion to the sphere with
some other scale tweeking and uses the spherical oblique stereographic

Based upon past performance, the new projections will be available
in a couple of weeks if I can correctly interpret the material on hand.
Note: documentation is being coded now and I am cutting some code
for the simple Gauss conversion.

When and if this material *ever* appears in GRASS software is a
speculation far beyond my realm of knowledge.

As for Snyder's version in proj the applicable projection parameters
are: <+ellps=> or <+a= and +es- or +rf= etc.>  +proj=stere +k_0=
+lat_0= +lon+0= +x_0= +y_0=.  How GRASS gets them into PROJ
need GRASS's manual(s).

On Mar 15, 2004, at 9:45 AM, <werchowyna at pf.pl> wrote:

> hello Everyone
> Thanks to you Gerald, Markus and Frank for your explanations on the 
> "proj"
> stuff in Grass.
> Despite of it I stiill don't know how to apply the desired projection 
> into
> Grass 5.03.
> Just in case here go the details once more:
> name: in Poland it's called Roussilhe or Quasi-Stereographic
> other names I saw: Roussilhe Oblique Stereographic
> described as: azimuthal, oblique, conformal
> <snip>

> _____________________________________
Jerry and the low riders: Daisy Mae and Joshua

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