Talk:Polyconic projection class

Local maps

Projections for smaller regions are in preparation. mdf 15:17, 16 October 2006 (UTC)

Replace low-contrast images

I will be replacing images on the various map projection pages. Presently many are on a satellite composite image from NASA that, while realistic, poorly demonstrates the projections because of dark color and low contrast. I have created a stylization of the same data with much brighter water areas and a light graticule to contrast. See the thumbnail of the example from another article. Some images on some pages are acceptable but differ stylistically from most articles; I will replace these also.

The images will be high resolution and antialiased, with 15° graticules for world projections, red, translucent equator, red tropics, and blue polar circles.

Please discuss agreement or objections over here (not this page). I intend to start these replacements on 13 August. Thank you. Strebe (talk) 22:46, 6 August 2011 (UTC)

File:American Polyconic projection.jpg to appear as POTD soon

Hello! This is a note to let the editors of this article know that File:American Polyconic projection.jpg will be appearing as picture of the day on July 8, 2016. You can view and edit the POTD blurb at Template:POTD/2016-07-08. If this article needs any attention or maintenance, it would be preferable if that could be done before its appearance on the Main Page. — Chris Woodrich (talk) 01:24, 23 June 2016 (UTC)

Picture of the day

The American Polyconic projection is a map projection conceptualized as "rolling" a separate cone tangent to the Earth at each parallel of latitude, rather than a single cone as in a normal conic projection. Each parallel is a circular arc of true scale. The scale is also true on the central meridian of the projection. This projection was in common use by many map-making agencies of the United States from the time of its proposal by Ferdinand Rudolph Hassler in 1825 until the mid-20th century.Map: Strebe, using Geocart

Looks great, Chris Woodrich! Many thanks. Strebe (talk) 16:31, 23 June 2016 (UTC)

"Chinese polyconic projection"

I deleted a series of edits by User:146.96.252.3 that mention a "Chinese polyconic projection". The projection it notes does appear to have a history of use in China, but the Chinese article on the topic does not have good sources, let alone ones available to an English encyclopædia. This appears to be a situation where some common phenomenon that you would expect to be notable has no WP:NOTABLE sources. If anyone has good information about this projection, we should figure out how to proceed with something more responsible than a poorly-sourced Chinese article and a commercial map. Strebe (talk) 18:27, 15 July 2017 (UTC)

Okay, I think I found a rigorous source for the projection in Section 12.4. This is encouraging. Strebe (talk) 18:33, 15 July 2017 (UTC)

But, unfortunately, the formulæ are incompletely described (what is b? and C? What are $\lambda _{i}$ and $\varphi _{i}$? etc.) and idiosyncratic (why is x-axis vertical)?Strebe (talk) 19:15, 15 July 2017 (UTC)

Okay, this appears to be the source. Strebe (talk) 19:28, 15 July 2017 (UTC)