I've been asked to look into a problem where our exported shapefiles are being displaced approximately 5.7m SSW from their true position.
Everything works as expected up to and including 1.7.4, but 1.8.0 and Master demonstrate the problem. KML files are ok as are shapefiles using other CRSs (e.g. EPSG:3857 - WGS 84 / Pseudo Mercator). If, using 1.8.0, I save a EPSG:27700 layer as a shapefile with a different CRS or as a KML file, the displacement is exported and loads as such in earlier versions of QGIS or external applications (Google Earth, ArcGIS). In 1.7.4 the layer metadata shows +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +towgs84=446.448,-125.157,542.06,0.15,0.247,0.842,-20.489 +units=m +no_defs while in 1.8.0 it shows +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +towgs84=375,-111,431,0,0,0,0 +units=m +no_defs The '+towgs84' parameters have changed. For anyone primarily using OSGB shapefiles (e.g. the approximately 10,000 UK town and parish councils who could use free Ordnance survey maps and QGIS) this leads to a major creditability problem if we wish to share data with other organisations. Has anyone else seen this problem? Andrew Chapman _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user