On Thu, 29 Oct 2009 15:54:44 +0700 Markus Nater <[email protected]> wrote:
> thank you Alex > and thank you Otto > > when I do take a projected coord system (set to wgs84 zone 47N), the > measurements are correct. > but then arises a new problem, as I have a raster shaded relief as > geotiff overlayed, that is referenced in wgs84. projection on the fly > makes this raster invisible... strangely! and I havent found out how to > work around this yet. i cant work out to reproject this raster either, > somehow nothing ever happens using the gdal raster translation. > any ideas how to solve this little problem? :-) your data in "wgs84 zone 47N" is probably something like: CRS: Projected Coordinate System "UTM zone 47N" Ellipsoid: WGS84 => EPSG: 32647 ? and the WGS 84 raster might be: CRS: Geographic Coordinate System "WGS84" Ellipsoid: WGS 84 => EPSG: 4326 ? that would mean your 2 layers are projected in 2 different CRS. QGIS supports OTF for vector layers. So you can load a raster, define its CRS, activate OTF and then load a vector layer projected in another CRS. Regards, Otto > cheers > markus > > > Alex Mandel schrieb: > > Markus Nater wrote: > > > >> Hi List > >> > >> I have some polygons in qgis with wgs84 projection. But when I try to > >> measure distance in meters, it gives me back 1cm for 0.1 degrees, which > >> is of course totally wrong. > >> how can I fix this, so I will have the correct measurements in meters? > >> > >> cheers > >> markus > >> > >> > > > > Enable projection on the fly, and pick a projected coordinate system. > > Technically in WGS84 the best you could get is great circle distances, > > and I'm not sure the measure tool does this yet. So you need to be in a > > projection that flattens the map evenly for distance measurement. > > > > Alex > > > > _______________________________________________ > > Qgis-user mailing list > > [email protected] > > http://lists.osgeo.org/mailman/listinfo/qgis-user > > _______________________________________________ Qgis-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-user
