<HTML dir=ltr><HEAD><TITLE>Re: [Proj] wgs84 northings and eastings</TITLE>
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<DIV dir=ltr><FONT color=#000000 size=2 face="Times New Roman">ED50 is not a projection. It is a datum, just like WGS84.</FONT></DIV>
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<FONT size=2 face=Tahoma><B>From:</B> proj-bounces@lists.maptools.org on behalf of Roger Oberholtzer<BR><B>Sent:</B> Tue 24-May-11 10:05<BR><B>To:</B> PROJ.4 and general Projections Discussions<BR><B>Subject:</B> Re: [Proj] wgs84 northings and eastings<BR></FONT><BR></DIV>
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<P><FONT size=2>On Tue, 2011-05-24 at 16:17 +0200, Jean-Claude Repetto wrote:<BR>> Le 24/05/2011 15:24, Roger Oberholtzer a écrit :<BR>> > I have had a request to provide locations (northings and eastings) in<BR>> > wgs84. Up to now, I have always worked with a specific projection<BR>> > somewhere in the world. Such a projection seems rather senseless to me.<BR>> > But there you have it. My question is, given wgs84 lat/longs, how would<BR>> > I request wgs84 northings / eastings from proj. Would this be adequate?<BR>> ><BR>> > +proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +a=6378137 +b=6378137 +units=m +no_defs<BR>> ><BR>> > Equally worrisome is that I am unsure how to test this as the requester<BR>> > has no sample data. Sigh...<BR>><BR>> If there is no projection, easting = longitude and northing = latitude.<BR><BR>In fact, this is how I have defined wgs84 up to now. In our system it is<BR>a handy way to get lat/longs that can then be projected somewhere else.<BR>In general use, however, we have always used some local projection<BR>(e.g., ED50 or whatever) to obtain northings /eastings, and were set for<BR>computing distances between points.<BR><BR>The problem is the person requesting this is not an expert in this area.<BR>They are convinced there is a single standard definition for WGS84 as a<BR>projection. As such, they feel they need to specify nothing more than<BR>'wgs84', and northings /eastings will just flow.<BR><BR>I thought maybe they knew something I did not know. Or that there is<BR>indeed a commonly accepted definition of wgs84 as a projection that I<BR>had missed.<BR><BR><BR><BR>Yours sincerely,<BR><BR>Roger Oberholtzer<BR><BR>OPQ Systems / Ramböll RST<BR><BR>Office: Int +46 10-615 60 20<BR>Mobile: Int +46 70-815 1696<BR>roger.oberholtzer@ramboll.se<BR>________________________________________<BR><BR>Ramböll Sverige AB<BR>Krukmakargatan 21<BR>P.O. Box 17009<BR>SE-104 62 Stockholm, Sweden<BR>www.rambollrst.se<BR><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></FONT> </P></DIV></BODY></HTML>