[Proj] Projection bounds question
Clifford J Mugnier
cjmce at lsu.edu
Thu Oct 24 11:16:59 EST 2013
Actually, coordinate systems used by military forces have traditionally published bounds. For instance, the Maroc Nord and Maroc Sud zones have an eastern limit to their Grids that are defined by the 448,000 meter Easting (X) coordinate of the North African ellipsoidal Bonne projection. The intersection of this Grid limit with the graticule was a graphical simplicity but a computational nightmare until the paper of Karl Rinner was used at Army Map Service. In the 1930’s, Professor Rinner published a paper (in German) detailing his development of the formulae for the ellipsoidal Bonne projection in series form. AMS developed a reversion of his series, and computational algorithms were developed for the North African Bonne in Morocco among other places. Most of the battle zones of WWII were in Grid Zones that had published boundaries, and some of the boundaries famously employed ellipsoidal loxodromes.
With regard to the UTM, the traditional bounds are three degrees on either side of the central meridian. At higher latitudes there are some noted exceptions, including the "zipper" in Northern Scandanavia with respect to the Military Grid Reference System (MGRS) which is based on the UTM.
Not common nowadays, bounds still exist for dozens of legacy Grid Systems.
People should read more of my publications ...
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
From: proj-bounces at lists.maptools.org [proj-bounces at lists.maptools.org] on behalf of Richard Greenwood [richard.greenwood at gmail.com]
Sent: Thursday, October 24, 2013 10:57 AM
To: PROJ.4 and general Projections Discussions
Subject: Re: [Proj] Projection bounds question
Coordinate systems do not generally have defined bounds although there may be laws that govern where a given coordinate system is to be used. In theory, you could represent any place on the earth in any coordinate system.
Regarding UTM, a given coordinate pair would be valid in any of the 60 UTM zones since false x and y are the same in every zone. Only the longitude origin changes between zones.
I don't know if this would be helpful in your case, but an interesting tool that was introduced at FOSS4G-NA this year can help make educated guesses about coordinate systems: http://projfinder.com/
richard.greenwood at gmail.com<mailto:richard.greenwood at gmail.com>
On Thu, Oct 24, 2013 at 3:11 AM, Tamas Szekeres <szekerest at gmail.com<mailto:szekerest at gmail.com>> wrote:
Is there a way to find out the bounds of a given projection?
Let’s say I have a given projection (UTM) and have a point (supposedly in the same utm) but I want to find out if that point is within the bounds of the projection.
Let me know if you have ideas.
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