Frank, Is there a way to add the towgs84 definition in the map file?
When I try that MS gives an error: msProcessProjection(): Projection library error. no options found in 'init' file The projection definition is this: 'init=epsg:27492 towgs84=-223.237,110.193,36.649' Thanks, Duarte Frank Warmerdam-2 wrote: > > DNC wrote: >> Hi all. >> >> Can anyone clarify how mapserver handles different datum in the map >> projection and in the layers projection when serving a wms service? >> Does MS apply datum transformations? If not, can it be done somehow >> without >> converting the layers? >> >> In my case I'm working with vector data, and have defined a map >> projection >> using "init=epsg:code" syntax. Then at the layer level I use the same >> syntax >> to declare the projection the data is in. >> And finally I want my WMS service to be published in 3 different datum >> and >> for that I advertise several epsg codes in the "wms_srs" metadata entry. >> >> I'm noticing a shift in images produced by MS that indicate a datum shift >> is >> not being applied. What can be done? > > Duarte, > > In general MapServer will apply a datum shift if you have datum > definitions > for the source and destination coordinate system. But often the > definitions > in the EPSG init file lack datum shift info and so nothing is done. > > So, start by examining the PROJ.4 definitions in the "epsg" init file and > see if they have +towgs84= or +nadgrids directives. You might also want > to > skim the material in the PROJ.4 FAQ about datums. > > Best regards, > -- > ---------------------------------------+-------------------------------------- > I set the clouds in motion - turn up | Frank Warmerdam, > [EMAIL PROTECTED] > light and sound - activate the windows | http://pobox.com/~warmerdam > and watch the world go round - Rush | President OSGeo, http://osgeo.org > > _______________________________________________ > mapserver-users mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/mapserver-users > > -- View this message in context: http://www.nabble.com/how-mapserver-handles-different-datum-projections-tp16517601p16518435.html Sent from the Mapserver - User mailing list archive at Nabble.com. _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users
