[Proj] Polyhedric projection

[Clifford J Mugnier]

Jan,



No, it is not possible to generate a correct global map using PROJ or any other application using the Polyhedric (Polyeder) projection.  It's an Aphylactic projection; not conformal, not azimuthal, not equal-area/authalic.  It IS easy to cast graphically from simple projection tables, which is why Aphylactics were popular in the 19th century by Topographers using plane tables and alidades in the field.  (Same goes for the Cassini-Soldner and the Polyconic.)



Check out my column on the Grids and Datums of Indonesia in Photogrammetric Engineering & Remote Sensing, October 2009 at www.ASPRS.org<http://www.ASPRS.org> .



Merry Christmas!



Clifford J. Mugnier, c.p., c.m.s.

Chief of Geodesy

LSU Center for GeoInformatics (ERAD 266)

Dept. of Civil Engineering (P.F. Taylor 3531)

LOUISIANA STATE UNIVERSITY

Baton Rouge, LA  70803

Academic: (225) 578-8536

Research: (225) 578-4578

Cell:             (225) 328-8975

honorary lifetime member, lsps

fellow emeritus, asprs

member, apsg

________________________________
From: proj-bounces at lists.maptools.org [proj-bounces at lists.maptools.org] on behalf of Jan Hartmann [j.l.h.hartmann at uva.nl]
Sent: Friday, December 21, 2012 7:44 AM
To: proj at lists.maptools.org
Subject: [Proj] Polyhedric projection

Hi all,

I'm working with a large bunch of maps of Indonesia, dating from the Dutch colonial period (1850-1946). Quite a few are in the so-called "polyhedral" projection, a simple projection that fits the globe locally for each separate map sheet. Works fine for a few sheets, but for larger surfaces it is impossible to generate a fitting map. Has anyone worked with this projection? Is it possible to generate a correct global map using proj?

Jan


See this passage in Snyder's book:

http://books.google.nl/books?id=0UzjTJ4w9yEC&pg=PA142&lpg=PA142&dq=polyhedric+projection&source=bl&ots=ZaeVIBxxA3&sig=Q437Wqb99b862kaqSYMRBTNS9f8&hl=nl&sa=X&ei=0WPUUPR0gaiEB7fjgKAE&ved=0CFwQ6AEwBg#v=onepage&q=polyhedric%20projection&f=false
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