[Proj] Two questions about Proj

Oscar van Vlijmen ovv at hetnet.nl
Fri Jan 20 03:25:14 PST 2006


> From: Andy Canfield <andy.canfield-gmail.com>
> Third question:
> Does it support translating coordinates to and from the old AT&T V&H
> coordinate system?

No.
Some time ago I found good working C code at:
<http://cpansearch.bulknews.net/markup/Geo-Coordinates-VandH-XS-0.01/XS.c>
Derived from a program obtained from an anonymous author within Bellcore by
way of the National Exchange Carrier Association. Cleaned up and improved a
bit by Tom Libert.
  
The code has forward AND inverse code. Not perfectly symmetrical, but very
adequate for normal V&H use.
See also the "Donald Elliptic Projection" discussed earlier in this list.
My test point:
lat=37d 42m 14.69s; lon=-82d 39m 15.27s;
V&H: 6363.235128, 2250.699791
The inverse gives: 37d 42m 14.7031s, -82d 39m 15.2701s
This projection is also used with West is positive convention.

V&H seems to be in use even today.
Originally used for calculating a 'billable' distance between telephone
calling centers.





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