Hi, The utm grid is way off or we have the wrong epsg code. If you geofence using 2 points (linear algo) using a service like google earth, you will see the distortion. The long lat coordinate are probably ok but I did not test them.
You can either use the long lat or use more points. With 4 points and using the thin plate spline, I got good results. Nicolas > Le 17 mai 2018 à 12:42, Carlos Henrique Grohmann de Carvalho > <[email protected]> a écrit : > > Thanks Nicolas, but the misalignment still persists. OTF is off, project has > same CRS as data (epsg 29192). There is a ~400m difference in the N-S > direction. > > Carlos > >> On Thu, May 17, 2018 at 1:28 PM, Nicolas Cadieux >> <[email protected]> wrote: >> Hi, >> Disable projection on the fly. Make sure the project is in the same CRS as >> your maps. >> Nicolas >> >>> Le 17 mai 2018 à 12:14, Carlos Henrique Grohmann de Carvalho >>> <[email protected]> a écrit : >>> >>> Hello all >>> >>> I have two pngs of topographic maps from southeastern Brazil (a zip file >>> with images and points is available here: >>> https://www.dropbox.com/s/mexeh4be46pgsk6/images_georef.zip?dl=0) >>> >>> I'm trying to georeference them, but with partial success only. In this >>> image (https://www.dropbox.com/s/37xxqp4fkwpdyqh/utm_error.png?dl=0) you >>> can see that the X coordinate is fine, but the Y coordinate of the two maps >>> won't match. >>> >>> Both maps use South American Datum 1969. I selected points near the edges, >>> and used the UTM values. >>> >>> Interestingly, if I use Lat/Long, and place the points at the corners, >>> using decimal degrees, the maps align perfectly. >>> >>> >>> Any help is appreciated >>> >>> >>> -- >>> Prof. Carlos Henrique Grohmann >>> Institute of Energy and Environment - Univ. of São Paulo, Brazil >>> - Digital Terrain Analysis | GIS | Remote Sensing - >>> >>> http://carlosgrohmann.com >>> http://orcid.org/0000-0001-5073-5572 >>> ________________ >>> Can’t stop the signal. >>> _______________________________________________ >>> Qgis-user mailing list >>> [email protected] >>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > > > > -- > Prof. Carlos Henrique Grohmann > Institute of Energy and Environment - Univ. of São Paulo, Brazil > - Digital Terrain Analysis | GIS | Remote Sensing - > > http://carlosgrohmann.com > http://orcid.org/0000-0001-5073-5572 > ________________ > Can’t stop the signal.
_______________________________________________ Qgis-user mailing list [email protected] List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
