I use these 7 coefficients with cartography in Catalonia (Spain), with right results:<br><br><div style="margin-left: 40px;"><span style="font-family: courier new,monospace;">
cs2cs +proj=latlong +datum=WGS84 +ellps=WGS84 +to +init=epsg:23031 +proj=utm +ellps=intl +zone=31 +units=m +towgs84=-
131.0320,-100.2510,-163.3540,1.2438,0.0195,1.1436,9.3900</span><br></div><br>More information:<br><br><div style="margin-left: 40px;"><a href="http://www.fomento.es/NR/rdonlyres/8B4D8323-5706-4F8F-84F7-C89774DCC2A1/29826/hercam.pdf" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
http://www.euref-iag.net/symposia/book2003/4-6.pdf</a><br></div><div style="margin-left: 40px;"><a href="http://www.fomento.es/NR/rdonlyres/8B4D8323-5706-4F8F-84F7-C89774DCC2A1/29826/hercam.pdf" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
http://www.fomento.es/NR/rdonlyres/8B4D8323-5706-4F8F-84F7-C89774DCC2A1/29826/hercam.pdf
</a><br></div><br>Jordi Gilabert Vall<br><div><span class="gmail_quote"><br></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">----------------------------------------------------------------------
<br><br>Message: 1<br>Date: Thu, 29 Nov 2007 14:55:17 +0100<br>From: Roger Oberholtzer <<a href="mailto:roger@opq.se">roger@opq.se</a>><br>Subject: RE: [Proj] WGS84 to ED50<br>To: "PROJ.4 and general Projections Discussions"
<br> <<a href="mailto:proj@lists.maptools.org">proj@lists.maptools.org</a>><br>Message-ID: <<a href="mailto:1196344518.25474.84.camel@acme.pacific">1196344518.25474.84.camel@acme.pacific</a>><br>Content-Type: text/plain; charset=UTF-8
<br><br>I have a bit more information on the problem with WGS84 lat/longs -><br>ED50(Spain) northings and eastings.<br><br>The software that is being used does not have a 'Spanish' setting. So<br>they have defined an ED50 7 parameter transform, with these
<br>coefficients:<br><br><br>> International Ellipsoid 1924 definition<br>> Mayor semiaxle: 6378388<br>> Minor semiaxle:6356911,9461<br>> 1/f:297<br>> Excentricity: 0.0819910890032286<br>><br>> About the 7 parameters transformation
<br>> Translation X (m): 125.098545<br>> Translation Y (m): 76.000054<br>> Translation Z (m): 156.198703<br>> X Rotation(seconds): 0<br>> Y Rotation(seconds): 0<br>> Z Rotation(seconds): -1.129<br>> Scale factor (ppm): -
8.30463103<br>><br>> This correspond with applanix header file saying<br>> Mapping frame datum: ED50_ESPAÑA ; a = 6378388.000000; 1/f = 297.000000;<br>> Coordinate transformation from WGS84 to mapping frame datum
<br>> dX = 125.098545; dY = 76.000054; dZ = 156.198703; f = 0.999991695369;<br>> R1 = 0.000000000000; R2 = 0.000000000000; R3 = -0.000005473550;<br>> sequence of the rotations: x,y,z,1<br>> Mapping frame projection : TM;
<br>> central meridian = -3.000000 deg;<br>> latitude of the grid origin = 0.000000 deg; grid scale factor = 0.999600:<br>> false easting = 500000.000000 m; false northing = 0.000000 m;<br>><br>><br>> Where Rotations are in radians
<br><br>I have tried setting proj to use this, as reported earlier in this thread, with no luck. I tried using the 7 parameters as<br>+towgs84=125.098545,76.000054,156.198703,0.0,0.0,-1.129,-8.30463103, but that made things worse.
<br><br>fromProj = pj_init_plus(<br> "+proj=latlong "<br> "+ellps=WGS84 "<br> "+no_defs");<br><br>toProj = pj_init_plus(<br>
"+proj=utm "<br> "+ellps=intl "<br> "+k=0.999600 "<br> "+x_0=500000.0 "<br> "+y_0=
0.0 "<br> "+zone=30 "<br> "+units=m"<br><br>"+towgs84=125.098545,76.000054,156.198703,0.0,0.0,-1.129,-8.30463103"<br> "+no_defs");
<br><br>So I am guessing I cannot simply use the 7 parameters as given. Correct?<br><br><br><br>--<br>Roger Oberholtzer<br><br>OPQ Systems / Ramböll RST<br><br>Ramböll Sverige AB<br>Kapellgränd 7<br>P.O. Box 4205<br>SE-102 65 Stockholm, Sweden
<br><br>Office: Int +46 8-615 60 20<br>Mobile: Int +46 70-815 1696<br><br><br><br>------------------------------<br></blockquote></div><br>