What is extruded globe?

[daan]

So you are the creator of extruded globe?

See above:

I am the creator; I can do with it as I like.

— daan

[Piotr]

So you are the creator of extruded globe?

See above:

I am the creator; I can do with it as I like.

— daan

I thought that this quote referred to Geocart, not extruded globe itself.

[daan]

List of projections in Geocart 3.2 that I invented:

• pseudocylindric equal-area polynomial
• simple pseudocylindric equal-area homotopy
• sinucyli
• Albers-Bonne homotopy
• Albers-Lambert homotopy
• Amulet
• equal-area pseudoconic
• heart
• shield
• apple
• equal-area polygon
• extruded globe
• fisheye
• hamusoidal
• kiss
• Strebe 1995
• Strebe asymmetric
• Strebe-sinudoidal
• Strebe-Snyder flat pole
• Strebe-Snyder pointed pole
• Strebe-Mollweide
• Strebe-Hammer
• lateral equidistant
• masque
• oblated Lagrange
• pseudorthographic

[Piotr]

And what are all possible Geocart projections intended for spherical (as opposed to cylindrical and conic I made in the past, as well as polyhedra and other shapes) globemaking?

There’s no well-defined answer to that. You can make globe gores from many pseudocylindric projections in transverse aspect, besides the usual polyconic, rectangular polyconic, globe gores projection, sinusoidal…

— daan

Are there any interruptions that are designed to cut least land with transverse? Below, shown Goode interrupted transverse Eckert IV, Goode interrupted transverse Sinusoidal and twelve–interrupted transverse Sinusoidal.

[daan]

Are there any interruptions that are designed to cut least land with transverse? Below, shown Goode interrupted transverse Eckert IV, Goode interrupted transverse Sinusoidal and twelve–interrupted transverse Sinusoidal.

Not that I know of.

— daan

[Piotr]

Uhh this is confusing. If there are no parameters beyond the equator then it doesn't make sense to define this beyond that. What users would expect from practical uses of this, is when users want more range they need more parameters, and vice-versa, if users don't want more parameters they get a hemisphere. Your way of mirroring is only leading to confusion, what is this meant for?

[daan]

Hello Piotr. It’s been awhile.

If there are no parameters beyond the equator then it doesn't make sense to define this beyond that.

What do you mean by a parameter beyond the equator? What is “this”?

What users would expect from practical uses of this, is when users want more range they need more parameters, and vice-versa, if users don't want more parameters they get a hemisphere. Your way of mirroring is only leading to confusion, what is this meant for?

What is “this”? What do you mean by “range”? What is “mirroring”? “More parameters” than what?

— daan

[Piotr]

Hello Piotr. It’s been awhile.

If there are no parameters beyond the equator then it doesn't make sense to define this beyond that.

What do you mean by a parameter beyond the equator? What is “this”?

What users would expect from practical uses of this, is when users want more range they need more parameters, and vice-versa, if users don't want more parameters they get a hemisphere. Your way of mirroring is only leading to confusion, what is this meant for?

What is “this”? What do you mean by “range”? What is “mirroring”? “More parameters” than what?

— daan

Mirroring in extruded globe: the spacing between 10° and 20° latitude North (towards azimuthal center) is the same as 10° and 20° latitude South (away from azimuthal center), etc. . when such a mirroring would not be useful for practical uses.

Extruded globe is used in a process of globemaking, in Geocart it acts like a custom azimuthal projection except for the mirroring, and the mirroring doesn't make sense because the real life process doesn't use the outer hemisphere projection in the first place so the mirrored spacing is confusing.

[daan]

I agree that the “mirroring” in this projection is arbitrary. I chose to extend the projection all the way to the opposite pole because it is better to extend it some way beyond the equator for a print “bleed”, but how much beyond is arbitrary. If arbitrary, then it might as well be all the way to the pole. If all the way to the pole, some method must be used.

— daan

[quadibloc]

It is your thinking and knowledge that are inconsistent. I did not limit Nicolosi globular or Fournier I; what is in Geocart are how those projections are defined by their inventors. If you do not like that, then feel free to conduct a séance and snottily berate their inventors for not fulfilling your obsessions centuries in advance.

I can understand that you feel that Piotr is not being polite.

However, I have to say he does have a point. In the case of the Nicolosi Globular, the extension of the projection beyond a single hemisphere is obvious and well-behaved. And it is even occasionally used: i.e. if 20 degrees W and 160 degrees E are the boundaries, one might extend the Eastern hemisphere to show the extra bit of Eurasia.

In the case of a projection claimed to be useful for making a globe by extrusion, since the physical operation of extrusion won't be well-behaved beyond a hemisphere, the mathematics of some of the projections that might work with it may also run into problems.

Basically, it seems to me he is arguing for the naive view that the range of projections should be limited when the extension would be useless or confusing; you are not limiting the range merely because of that - but you will limit the range if an extension of the range is not included in the genuine historical official definition of the projection. Which is sound by purist academic standards, but to many other people it would seem like a much less important reason for limiting a projection's range. Even if the result in some sense doesn't deserve to be called a Nicolosi globular (or whatever) in that case.