Search found 313 matches

by Piotr
Fri Apr 24, 2020 7:18 am
Forum: Map projections
Topic: Experimental projections
Replies: 30
Views: 1229

Re: Experimental projections

Hufnagel and HEALPix are modern projections that relax the requirement of monotonically decreasing parallel length. Denoyer relaxes the constraint of constant scale along parallels. Relaxing that latter constraint is not a definition I would use, ever. — daan The Denoyer's relaxation seems to be al...
by Piotr
Thu Apr 23, 2020 5:11 am
Forum: Map projections
Topic: Experimental projections
Replies: 30
Views: 1229

Re: Experimental projections

And the tristandard experimental projection makes this false: In a pseudocylindric projection, the only parallel that could be conformal is the equator. The only other points that could be conformal would be along the central meridian. This series is pseudocylindric. Therefore none of them are confo...
by Piotr
Thu Apr 23, 2020 5:05 am
Forum: Problems with Geocart 3
Topic: What is the reasoning for the asymmetrical boundaries of Miller oblated stereographic?
Replies: 5
Views: 104

Re: What is the reasoning for the asymmetrical boundaries of Miller oblated stereographic?

At least it’s a bug that lets you create funny if useless projections… ;) Or it could be used to map oval-shaped regions, even though this projection was meant to map one specific region, just like how GS50 could be used to map US-shaped regions, or Mercator could be used to map great circle shaped...
by Piotr
Wed Apr 22, 2020 9:10 pm
Forum: Map projections
Topic: Experimental projections
Replies: 30
Views: 1229

Re: Experimental projections

Of course it looks funny, but as it's just presented as an experimental projection, that's not really a valid criticism. However, it doesn't seem to be equal-area. With that constraint removed, it's trivially easy to do so much better: http://www.quadibloc.com/maps/images/merla.gif No shearing dist...
by Piotr
Wed Apr 22, 2020 11:05 am
Forum: Map projections
Topic: Experimental projections
Replies: 30
Views: 1229

Re: Experimental projections

tristandard projection — a pseudocylindrical projection that uses a fitted quartic polynomial to achieve three standard parallels (-60, 0, 60) that have no shearing distortion whatsoever.
Image
by Piotr
Wed Apr 22, 2020 7:21 am
Forum: How to
Topic: What is Add test page items?
Replies: 6
Views: 122

Re: What is Add test page items?

daan wrote:
Wed Apr 22, 2020 7:19 am
Which you know very well is false. Hopefully you’re finished trolling now. If not, well…

— daan
Why do you keep saying "you know very well"
by Piotr
Wed Apr 22, 2020 1:21 am
Forum: Problems with Geocart 3
Topic: What is the reasoning for the asymmetrical boundaries of Miller oblated stereographic?
Replies: 5
Views: 104

Re: What is the reasoning for the asymmetrical boundaries of Miller oblated stereographic?

daan wrote:
Tue Apr 21, 2020 7:39 am
The projection is defined for a particular aspect and is not meaningful with a different aspect. The boundaries have been defined against that aspect.

— daan
So why is then there an option to change aspect?
by Piotr
Wed Apr 22, 2020 12:18 am
Forum: How to
Topic: What is Add test page items?
Replies: 6
Views: 122

Re: What is Add test page items?

I'm starting to think that Snyder described the entire software, and you are the one implementing it.
by Piotr
Tue Apr 21, 2020 8:08 am
Forum: Map projections
Topic: On distortion and optimal projections
Replies: 94
Views: 3413

Re: On distortion and optimal projections

What about a world map? With world maps, you have to be careful and state clearly what you mean: a world map that is only ripped at one point, like an azimuthal projection? A world map that is ripped along an entire meridian like the maps I show on this page? Something else? If you only interrupt a...
by Piotr
Tue Apr 21, 2020 7:13 am
Forum: Problems with Geocart 3
Topic: What is the reasoning for the asymmetrical boundaries of Miller oblated stereographic?
Replies: 5
Views: 104

What is the reasoning for the asymmetrical boundaries of Miller oblated stereographic?

Image

Those four maps are the same, but they have different boundaries, even though they are unconstrained.