Elliptical stereographic

[RogerOwens]

I didn't say "conformal" anywhere.

Also, I said that the spacing of parallels is like in Stereographic, Gall stereographic or Foucaut.

Ok, I misundserstood, and thought that the map was intended to be conformal.

But wouldn't the Stereographic's parallel-spacing be too extreme for an ellipse? And, even with Gall-Stereographic spacing in an ellipse, wouldn't that make the Arctic awfully skinny?

But a bit of narrowing in high latitudes has been used to reduce Arctic flattening, with Gall Stereographic spacing, and to slightly reduce Arctic magnification. At least I suppose that''s the rationale of the Times projection. It uses Gall Stereographic spacing, with slightly curved sides. It's probably a pseudocylindrical, but the sides are only slightly curved.

I guess its justification is that it's Gall Stereographic, but with less Arctic squashing, and a little less Arctic magnifications (but still quite a bit).

Michael Ossipoff

[Piotr]

No, I'm just curious for stereographic and Van der Grinten III spacing. Ellipse ratios I want are 2:1, 1:1, correct scale at equator and correct scale at 45, 0.

[Piotr]

Using Gall Stereographic in 2:1 ratio as the database (with built-in graticule) and using Apian II and stretching vertically by 4÷pi gives me this, which is the third request:



In a circle (second request):



The database itself:

[Piotr]

but what vertical stretch will give me 45° standard parallel?

[daan]

but what vertical stretch will give me 45° standard parallel?

Use the Info palette to show you the distortion at 45°. Then use Stretch and Rotation to counteract the distortion values you find there.

— daan

[Piotr]

but what vertical stretch will give me 45° standard parallel?

Use the Info palette to show you the distortion at 45°. Then use Stretch and Rotation to counteract the distortion values you find there.

— daan

That won't work in practice. I used a custom database to have a different parallel spacing, so the Info "palette" will show me the distortion for the underlying Apian II.