Questions regarding Györffy’s paper

[quadibloc]

Still, no luck on the polyconic.

Looking at the image in which you noted that you were doing something wrong, my guess would be that if you took the formulat used for that image, and changed it as follows:

x' = y/lat
y' = x

you would have something that looked more like a conventional map projection, even if it still wasn't the one you wanted. ("lat" should really be the latitude divided by 90 degrees South so that 90 degrees North becomes -1.)

[Atarimaster]

my guess would be that if you took the formula used for that image, and changed it as follows:
(…)

Thank you, but the problem has already been solved. I guess I didn’t report that, sorry.

By the way, did you notice that Frančula XII and XIII are quite similar to one of your own projections you showed at your Ginzburg page? (The second to last image on that page.)


And – off-topic in this thread, but I’d like to mention it anyway –, on your August Conformal page, I recently saw you using the NOAA “Topography and Bathymetry“ dataset. I instantly liked the black/dark grey oceans but I was not so fond of the way the continents look. So I modified one of my own elevation maps to have oceans in the same style.
Here’s my current result, projected to Ginzburg V:

ginzburg-5-blackocean.jpg (117.58 KiB) Viewed 1742 times

It’s not exactly what I had in mind (I still might work a bit on the colors used on land), but it was close enough for me to use it in my 2021 map projection calendar.
By using the NOAA image on your website, you gave me the idea. So thank you!

[quadibloc]

Thank you, but the problem has already been solved. I guess I didn’t report that, sorry.

No, it's my fault for not carefully reading the thread. The solution was the image where there was still one tiny error, line segments sticking out from the Equator.

[mapnerd2022]

Györffy is definitely jumping to conclusions. There is no research to back up that opinion, so it ought to have been expressed as a conjecture. For my own part, it’s not even a credible conjecture. People are all over the map in their preferences for map projections. Individuals are malleable in that preference. Even a population is malleable over time.

I don’t know what projection he refers to by “ordinary polyconic” subjected to Umbeziffern. Possibly it’s one of the many Russian polyconic modifications from the mid 20th century, such as by Taich or Ginzburg or by the Khar’Kov Engineering Construction Institute, as mentioned by Snyder in Flattening the Earth. I don’t have enough information about those, other than the incomplete set of Ginzburg projections in Geocart.

— daan

Maling does tell us that «Several interesting modifications of the simple polyconic projection have been proposed.» Meaning presisely, for example, the ones by G.A.Ginzburg and T.D.Salmanova.

[Atarimaster]

Maling does tell us that «Several interesting modifications of the simple polyconic projection have been proposed.» Meaning presisely, for example, the ones by G.A.Ginzburg and T.D.Salmanova.

Thank you!
From which Maling text does the quotation come?
However, meanwhile I know that Györffy indeed was referring to the Frančula projections.

[mapnerd2022]

It comes from his paper called «A review of some Russian map projections.»

[mapnerd2022]

The «simple polyconic» meaning the American, ordinary or simply Polyconic projection.

[Atarimaster]

It comes from his paper called «A review of some Russian map projections.»

Thank you!

[mapnerd2022]

You're welcome! BTW I'm the one who corrected the Erdi-Krauz projection's classification on your website.