Absolute average

[Piotr]

By "same scale" I mean set the nominal scale of both to average of nominal scales of both.

[daan]

Do you mean to set the scale of the result to the average scale of the two sources while using the original scale of each source to perform the blend, or do you mean to use the average scale of the two sources as the scale of each source in order to computer the blend?

— daan

[Piotr]

I do mean to use the average scale of the two sources as the scale of each source in order to computer the blend. (computer the blend? what does that mean?)

[daan]

I do mean to use the average scale of the two sources as the scale of each source in order to computer the blend. (computer the blend? what does that mean?)

“compute the blend” is what I intended.

What use would this requested feature have? Instead, just set the nominal scale to be the same before blending. Or set them to you whatever you want. That gives the most flexibility with the least complication.

— daan

[Piotr]

Absolute average for same projections can be interesting in some situations, like averaging normal and transverse aspects.

[daan]

There is no known area-preserving combination of two arbitrary equal-area projections.

That was true when I wrote that. Today I discovered a method to do this. A paper is forthcoming.

— daan

[Atarimaster]

There is no known area-preserving combination of two arbitrary equal-area projections.

That was true when I wrote that. Today I discovered a method to do this. A paper is forthcoming.

Wow, that sounds interesting!
I’m anxious to learn about it.
Hopefully, this method will find its way into Geocart?

Kind regards,
Tobias

[Piotr]

Wow! That means that in the future, we may be able to combine Hammer and Smyth equal-surface and get an equal-area projection!

[daan]

Wow! That means that in the future, we may be able to combine Hammer and Smyth equal-surface and get an equal-area projection!

Here you go.

Smyth weight = 0.1

SH0.1.jpg (103.07 KiB) Viewed 2168 times

Smyth weight = 0.2

SH0.2.jpg (100.33 KiB) Viewed 2168 times

Smyth weight = 0.5

SH0.5.jpg (93.3 KiB) Viewed 2168 times

Smyth weight = 0.8

SH0.8.jpg (83.08 KiB) Viewed 2168 times

I suspect, though, that there is a simpler analytic parameterization in this particular case.

— daan

[Atarimaster]

They look like equal-area results from the generalized Wagner.
Which of course isn’t astonishing at all, given the thought that both Hammer and all cylindric equal-area projections can be obtained by the generalized Wagner.

(Although for cylindric and pseudocylindric projections, I’d rather recommend Hufnagel because it has a greater variety in the results and saves you the trouble of certain rounding errors…)