[Proj] The world of ECEF aka geocentric coordinates

Gerald I. Evenden geraldi.evenden at gmail.com
Tue Feb 3 12:19:49 EST 2009

On Tuesday 03 February 2009 11:43:00 am Clifford J Mugnier wrote:
> Local Space Rectangular (LSR) is the approximately  60-70 year old
> terminology used in computational photogrammetry.
> Polyhedric (Polyeder in Dutch or German) is the 19th century terminology
> for the "projection."  (Also known as the "Tampico Datum" from the 1920s or
> 1930s.)
> C. Mugnier

If age has priority, it would seem to be a winner but "Rectangular' seem a 
little open to interpretation.

> From: proj-bounces at lists.maptools.org on behalf of Karney, Charles
> Sent: Tue 03-Feb-09 04:19
> While we're at it, what's the consensus for the terminology for the
> Cartesian system with origin at z = 0 tangent to ellipsoid, z up, y
> north?  Choices so far:
>     local Cartesian
>     ENU
>     topocentric

I do have trouble with ENU because of the conflict introduced with 
Easting-Northing as part of its name and the same usage of EN with 
cartographic projections.

There is nothing in the other names that mentions the property of the XY plane 
being tangential to the ellipsoid although the U[p] might imply such.  "Topo" 
does not cut it with me as it has too much baggage with other usage.

How about "[Ellipsoid] Tangential Cartesian" or ETC.

Hey, man!  That's got it!

> It seems that topocentric is the best, and this doesn't tie you down to
> Cartesian coordinates.  Transforming to polar gives azimuth-elevation-
> distance.
> --
> Charles Karney <ckarney at sarnoff.com>
> Sarnoff Corporation, Princeton, NJ 08543-5300

The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist

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