[PROJ] "Local" projection method?

[Nyall Dawson]

On Sat, 26 Sep 2020 at 07:02, Even Rouault <even.rouault at spatialys.com> wrote:
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> On jeudi 24 septembre 2020 11:01:22 CEST Even Rouault wrote:
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> > On jeudi 24 septembre 2020 05:42:22 CEST Kristian Evers wrote:
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> > > Nyall,
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> > >
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> > > > Based on this, would it be appropriate to directly map this projection
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> > > > method across to the "Orthographic" method? Or am I missing something
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> > > > important?…
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> > >
>
> > > Yes, it would seem so. Be aware though, the current Orthographic
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> > > projection
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> > > implementation in PROJ is only valid in the spherical case. You would have
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> > > to extend that to the ellipsoidal case for the mapping described by Esri.
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> > > We’ve got an old issue [0] which contains some hints on how to go about
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> > > that.
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> >
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> > "Recent" EPSG guidance note 7.2
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> >
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> > https://drive.tiny.cloud/1/4m326iu12oa8re9cjiadxonharclteqb4mumfxj71zsttwkx/
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> > 62018e48-9da4-43e7-b598-1202cd96ec9f
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> >
>
> > (link got from epsg.org)
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> >
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> > has the maths for the ellipsoidal formulation of the orthographic projection
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> > in paragraph 3.3.5, page 89
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>
>
> I gave this a try at https://github.com/OSGeo/PROJ/pull/2361
>
> with mapping from ESRI WKT Local to +proj=ortho

Thanks Even -- that's much appreciated!!

Nyall