Authalic and Conformal latitudes

Discussion of things we want in Geocart
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Piotr
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Joined: Thu Mar 23, 2017 12:27 pm

Authalic and Conformal latitudes

Post by Piotr »

Name tells.

Image

Authalic latitude - square grid on 3:1 ratio cylindrical equal area, since pi:1 ratio in Lambert's is irrational.

Conformal latitude - square grid on Mercator.

Edit: I found 0, 14.5, 30, 48.5, 90 to be more accurate for authalic latitude.
daan
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Re: Authalic and Conformal latitudes

Post by daan »

I don’t understand this posting.
:?

— daan
Piotr
Posts: 313
Joined: Thu Mar 23, 2017 12:27 pm

Re: Authalic and Conformal latitudes

Post by Piotr »

Authalic latitude - parallels are spaced on a sphere or ellipsoid so that the world is split into equal areas. Take a cylindrical equal-area projection with 3:1 ratio and draw a square grid on it.

Conformal latitude - Take a Mercator and draw a square grid on it.
daan
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Re: Authalic and Conformal latitudes

Post by daan »

Sorry; I’m still completely lost.

Are you making an observation of some kind? Are you proposing something? What does Lambert azimuthal equal-area have to do with the 3:1 cylindrical equal-area that you mention? What does the stereographic have to do with the Mercator that you mention? What does the square grid on Mercator have to do with conformal latitudes?

I guess you are illustrating what happens when you deproject a square grid on a Mercator to the globe, and then project that onto stereographic? And likewise for Lambert azimuthal? But why?

— daan
Piotr
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Joined: Thu Mar 23, 2017 12:27 pm

Re: Authalic and Conformal latitudes

Post by Piotr »

No. These grids are alternative graticule options instead of standard equidistant one. These grids then can be shown on any projection.
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