[OSRS-PROJ] Inverse function of a quadrant is wrong?

[Clifford J Mugnier]

Gerald,

If you're looking at Equivalent Spheres, an extra bit of heartburn can be
garnered from a perusal of General Jean Laborde's Oblique Mercator of
Madagascar.  The dear general did, in fact, use a constant of integration.
It only took me a week or so (MANY years ago) to duplicate that one with an
HP calculator ...

Cliff Mugnier
LOUISIANA STATE UNIVERSITY

You lost me.  I can understand an animation of shifting origin but
I do not understand the need for the inverse.  Secondly, if the
animation is more-or-less global in extent the spherical form
would seem more appropriate.

None of this excuses the apparent failure of PROJ.4 to do a
proper inverse.

This all brings me back to my recent nemesis: the Gaussian Sphere:
I still have not resolved the differences between Snyder, Thomas,
Pearson, Swiss Projection, Krovak and alternate stereographic.
Some of these folk have elided the constants of integration
and I can't figure out why and what justification was used.
Are there any good mathematical cartographers out there who
have been through this material?

Snyder seems to use the conformal sphere as an intermediate
step in the stereographic but I can' simply match the procedures
with what I have done with the other examples.  AARRRRGGGHHHH!

On Wed, 2003-04-09 at 16:56, Alexander Weidauer wrote:
> Hi Gerald,
>
> Ok I've tested it with other proj oringins but was confused by the
> results. So I went back to lat_0=0, lon_0=0. I can test it for other
> origins. The aim of my application is to show the usage of proj api
> in an animation so I start to calculate NAN conditions for stere
> initial origins. I want to create a animation over a moving origin
> with a world map and a grid and render the image set.
>
> Thanks Alex
...

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