Hi Nick, I have my layers in a PostGIS database with a structure like:
Original Table: id integer zone integer the_geom geometry I originally created the table using the 'shp2pgsql' to convert from a shapefile. The process to change the geometry I used was to create a new table with the geometry column transformed using the st_transform function: select id, zone, st_transform (the_geom, 4269) as the_geom into degree_projection_table from meter_projection_table_26717 ; Then I create a new layer in Geoserver from this modified table and check what the layer looks like in OpenLayers. I haven't used either of the tools you mention but its my understanding that the st_transform function is standards based so should be available via an API. Regards, Mike > Hi Mike, > > if you could just tell me which tools to use to do that (GDAL or > Shpproj) I'd be really grateful. > best, > Nick > > On Wed, Jun 10, 2009 at 1:04 PM, Michael O'Cleirigh > <[email protected] <mailto:[email protected]>> > wrote: > > Hello, > > I had a similar type of problem with WMS in OpenLayers when > showing a layer served through Geoserver. i.e. The features were > offset incorrectly when reprojected onto a Google Maps base layer. > > My source layer is in the NAD 83 UTM Zone 17N EPSG:26917 > projection. But in order to get it to reproject to the Google > EPSG:900913 properly I needed to first convert the layer into > standard NAD 83 degree unit projection (4269). > > I see that EPSG:32632 is similar to 26917 in that its unit is > meter. Can you try converting the layer into the appropriate > WGS84 degree projection first and see if that helps? > > Regards, > > Mike > >> Hi Jan, >> >> Unless I am very much mistaken, >> http://www.dmap.co.uk/utmworld.htm shows Tunisia to be squarely >> in UTM 32 N. I have ArcGIS and my landsatt data for the region >> all fall into UTM 32 N, which is why I believe this is in fact >> the case. >> >> >> UTM Zone 32 N is also EPSG:32632 >> >> http://spatialreference.org/ref/epsg/32632/ so I still don't know >> what going on. >> >> UTM coordinates are arbitrary cartesian points, which basically >> could end up anywhere which is why the UTM zone is needed for the >> origin. The only thing I can think is that yes, there is some >> issue with the projection, but I don't know what. >> >> On Wed, Jun 10, 2009 at 12:38 PM, Jan Martin >> <[email protected] <mailto:[email protected]>> wrote: >> >> Hi Nicholas, >> >> your assumption regarding your source UTM Zone beeing UTM 32N >> is wrong. >> >> Your coordinates are from Tunisia. And Tunisia is UTM 32S, >> not UTM 32N: >> >> http://upload.wikimedia.org/wikipedia/commons/8/85/LA2-Africa-UTM-zones.png >> >> But as you can see here EPSG:32632 is the right result of a >> conversion from UTM Zone 32S to EPSG: >> http://spatialreference.org/ref/epsg/?search=32632&srtext=Search >> <http://spatialreference.org/ref/epsg/?search=32632&srtext=Search> >> >> Question remains why your coordinates from Tunisia are >> displayed in Algeria. >> >> I wonder if it is OK to just use EPSG:32632 as a projection >> for your data, or if one would have to do math on the >> coordinates to. >> After all your coordinates have been recorded in *WGS84, UTM >> 32S.* >> >> Jan >> >> On Wed, Jun 10, 2009 at 6:08 PM, Nicholas Efremov-Kendall >> <[email protected] <mailto:[email protected]>> wrote: >> >> >> Hello all, >> >> I believe this is more of a gis question, than for >> OpenLayers, but the problem manifests itself in >> openlayers and I'm having some trouble diagnosing it. Jan >> provided me with some very helpful assistance, which led >> me to the conclusion that my projection was wrong. I'm >> trying to display gps point originally recorded in UTM >> 32N. I had mistakenly believed this was EPSG 22332, but >> 36232 is actually what I was going for. My problem is >> this: I have the points overlaid on a wms server (thanks >> to Jan) but they're in the wrong spot. However, when I >> change the EPSG code, the points don't move. Does anyone >> have a suggestion for why they don't move? and or for how >> to crack this nut. >> best, >> Nick >> >> >> _______________________________________________ >> Users mailing list >> [email protected] <mailto:[email protected]> >> http://openlayers.org/mailman/listinfo/users >> >> >> >> ------------------------------------------------------------------------ >> _______________________________________________ Users mailing >> list [email protected] <mailto:[email protected]> >> http://openlayers.org/mailman/listinfo/users > > > _______________________________________________ > Users mailing list > [email protected] <mailto:[email protected]> > http://openlayers.org/mailman/listinfo/users > > _______________________________________________ Users mailing list [email protected] http://openlayers.org/mailman/listinfo/users
