[Proj] conversion latlong to UTM (& vice versa)

[Clifford J Mugnier]

The Military Grid Reference System is based on the UTM Grid.  The
alphanumeric system will allow identification of the specific UTM Zone and
therefore an avenue to compute the inverse to Latitude and Longitude, since
the MGRS is designed as to NOT repeat the same alphanumeric coordinates in
adjacent zones.  (Prevents "friendly fire" from indirect artillery
support.)  Without MGRS for a clue, there is no possible way to figure out
a particular zone unless you have some vague idea where the coordinates are
and can make an intelligent guess regarding the magnitude of the Eastings
(greater than 500K or less than 500K) in an area bounded by ONLY two zones.

Same rationale would work for areas near the equator.

My two cents ...

Clifford J. Mugnier, C.P., C.M.S.
National Director (2006-2008),
Photogrammetric Applications Division
American Society for Photogrammetry and Remote Sensing
and
Chief of Geodesy,
CENTER FOR GEOINFORMATICS
Department of Civil Engineering
CEBA 3223A
LOUISIANA STATE UNIVERSITY
Baton Rouge, LA  70803
Voice and Facsimile:  (225) 578-8536 [Academic]
Voice and Facsimile:  (225) 578-4474 [Research]
Honorary Life Member of the
Louisiana Society of Professional Surveyors
======================================================
http://www.asprs.org/resources/GRIDS/
http://appl003.lsu.edu/eng/ceeweb.nsf/$Content/Mugnier
======================================================


On Thu, 2006-11-02 at 16:22 +0700, oon at informatika.org wrote:
> Dear All Proj user,
>
> I want to convert coordinate with datum WGS84, from latlong projection
> to UTM projection
> (and vice versa).
>
> If I convert from latlong projection to UTM projection,
> I can get the UTM zone from UTM definition, so I can calculate the zone
> from it's longitude.
>
> If I'm doing vehicle tracking with UTM projection,
> and the vehicle moving between UTM zones,
> How should I do to get UTM zone of current position of vehicle?
> (so I can convert UTM to latlong again).
>
> Is it any statement or definition of UTM that declare
> how to get UTM Zone from UTM coordinate?
>
> Is it any Proj utilities (function/procedure) that support my problem?

Not exactly an answer here, but we provide locations from moving
vehicles as well. In the countries that are UTM and span more than one
zone, it is quite often the case that one zone is chosen as the one used
in all calcs in the country. In Spain, for example, it is the zone where
Madrid is. In Finland it is Helsinki. In Saudi Arabia it is Riyadh. So,
maybe that is an approach. This is mostly useful for GIS-type apps more
than those wanting to find absolute locations. Of course, all your data
must agree with this.

--
Roger Oberholtzer

OPQ Systems AB
Ramböll Sverige AB
Kapellgränd 7
P.O. Box 4205
SE-102 65 Stockholm, Sweden

Tel: Int +46 8-615 60 20
Fax: Int +46 8-31 42 23

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