<HTML dir=ltr><HEAD><TITLE>Re: [Proj] The world of ECEF aka geocentric coordinates</TITLE>
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<DIV dir=ltr><FONT face="Times New Roman" color=#000000 size=2>The 5th edition of the <STRONG><EM>Manual of Photogrammetry</EM></STRONG> (2004) page 189, section 3.1.2.2 gives the equations and refers to this as "Local Space Rectangular." (That's the entire page.) I believe the earlier edition of the <EM>Manual</EM> and <EM>ESRI</EM> are incorrect in their terminology for this coordinate system. If I recall correctly, the <U>3rd</U> edition of the <EM>Manual</EM> agrees with the <U>5th</U> edition ...</FONT></DIV>
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<DIV dir=ltr><FONT size=2>I don't agree with Roger Lott's (EPSG) notes, either.</FONT></DIV>
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<DIV dir=ltr><FONT size=2>I vote for LSR, especially since I wrote <U>that</U> chapter for the 5th edition of the <STRONG>Manual of Photogrammetry</STRONG> (2004).</FONT></DIV>
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<DIV dir=ltr><FONT size=2>So there. I call your bet.</FONT></DIV>
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<DIV dir=ltr><FONT size=2>:-)</FONT></DIV>
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<DIV dir=ltr><FONT size=2>C. Mugnier</FONT></DIV>
<DIV dir=ltr><FONT size=2>LSU</FONT></DIV></DIV>
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<DIV dir=ltr><FONT face=Tahoma size=2><B>From:</B> proj-bounces@lists.maptools.org on behalf of Noel Zinn<BR><B>Sent:</B> Tue 03-Feb-09 12:25<BR><B>To:</B> 'PROJ.4 and general Projections Discussions'<BR><B>Subject:</B> Re: [Proj] The world of ECEF aka geocentric coordinates<BR></FONT><BR></DIV>
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<P><FONT size=2>The 4th edition of the Manual of Photogrammetry (1980) page 485 section<BR>9.4.2.3.6.2 (phew!) gives the equations and refers to this as<BR>"geocentric-local vertical". I believe ESRI uses the same name for this<BR>coordinate conversion in their software.<BR><BR>Bugayevskiy and Snyder (1995) on page 3 section 1.1.2 (right up front in<BR>their "Map Projections A Reference Manual") call this the "topocentric<BR>horizon coordinate system" and give different equations than the Manual of<BR>Photogrammetry (due to a different, more cumbersome derivation). In fact,<BR>both citations are equivalent mathematically with a little additional<BR>manipulation.<BR><BR>EPSG terminology is "topocentric coordinate system". See section 2.2.2 of<BR>Guidance Note 7-2 at www.epsg.org which offers forward and reverse<BR>equations.<BR><BR>Now, it turns out that if you throw away the U of this ENU of this<BR>coordinate system you have the (exact) ellipsoidal form of a perspective map<BR>projection, the orthographic. Unfortunately, Bugayevskiy and Snyder, after a<BR>cumbersome derivation that tosses the high order terms of the series they<BR>invoke, offer an approximate form of the ellipsoidal orthographic on page<BR>116 (when the exact form was stated on page 3).<BR><BR>I vote for topocentric coordinates.<BR><BR>Noel Zinn<BR><BR>-----Original Message-----<BR>From: proj-bounces@lists.maptools.org<BR>[<A href="mailto:proj-bounces@lists.maptools.org">mailto:proj-bounces@lists.maptools.org</A>] On Behalf Of Gerald I. Evenden<BR>Sent: Tuesday, February 03, 2009 11:20 AM<BR>To: PROJ.4 and general Projections Discussions<BR>Subject: Re: [Proj] The world of ECEF aka geocentric coordinates<BR><BR>On Tuesday 03 February 2009 11:43:00 am Clifford J Mugnier wrote:<BR>> Local Space Rectangular (LSR) is the approximately 60-70 year old<BR>> terminology used in computational photogrammetry.<BR>><BR>> Polyhedric (Polyeder in Dutch or German) is the 19th century terminology<BR>> for the "projection." (Also known as the "Tampico Datum" from the 1920s<BR>or<BR>> 1930s.)<BR>><BR>> C. Mugnier<BR><BR>If age has priority, it would seem to be a winner but "Rectangular' seem a<BR>little open to interpretation.<BR><BR>> From: proj-bounces@lists.maptools.org on behalf of Karney, Charles<BR>> Sent: Tue 03-Feb-09 04:19<BR> ...<BR>> While we're at it, what's the consensus for the terminology for the<BR>> Cartesian system with origin at z = 0 tangent to ellipsoid, z up, y<BR>> north? Choices so far:<BR>><BR>> local Cartesian<BR>> ENU<BR>> topocentric<BR><BR>I do have trouble with ENU because of the conflict introduced with<BR>Easting-Northing as part of its name and the same usage of EN with<BR>cartographic projections.<BR><BR>There is nothing in the other names that mentions the property of the XY<BR>plane<BR>being tangential to the ellipsoid although the U[p] might imply such.<BR>"Topo"<BR>does not cut it with me as it has too much baggage with other usage.<BR><BR>How about "[Ellipsoid] Tangential Cartesian" or ETC.<BR><BR>Hey, man! That's got it!<BR><BR>> It seems that topocentric is the best, and this doesn't tie you down to<BR>> Cartesian coordinates. Transforming to polar gives azimuth-elevation-<BR>> distance.<BR>><BR>> --<BR>> Charles Karney <ckarney@sarnoff.com><BR>> Sarnoff Corporation, Princeton, NJ 08543-5300<BR><BR>--<BR>The whole religious complexion of the modern world is due<BR>to the absence from Jerusalem of a lunatic asylum.<BR>-- Havelock Ellis (1859-1939) British psychologist<BR>_______________________________________________<BR>Proj mailing list<BR>Proj@lists.maptools.org<BR><A href="http://lists.maptools.org/mailman/listinfo/proj">http://lists.maptools.org/mailman/listinfo/proj</A><BR><BR>_______________________________________________<BR>Proj mailing list<BR>Proj@lists.maptools.org<BR><A href="http://lists.maptools.org/mailman/listinfo/proj">http://lists.maptools.org/mailman/listinfo/proj</A><BR></FONT></P></DIV></BODY></HTML>