Hi I usually do what you want to do, but this step seems a little bit odd "Now, using Google Maps I selected four specific well and easy referenced points into the image to get geographics coordinates (longitude and latitude)" Check this video, is in Spanish and it shows how to reference using a layer of points and your rasterHope it helps
Gerardo Jiménez Delgado Instituto de Investigaciones Antropológicas Universidad Nacional Autónoma de México Ciudad Universitaria s/n Coyoacan 04510 Mexico City Mexico 56 22 95 16 Date: Sun, 10 Mar 2013 23:27:20 -0600 From: padillarauda...@gmail.com To: gregorio_i...@yahoo.com.mx CC: Qgis-user@lists.osgeo.org Subject: Re: [Qgis-user] Raster image is georeferenced to UTM projection. Doubt about CRS. WSG 84 2013/3/10 Gregorio Inda <gregorio_i...@yahoo.com.mx> Hi, I am new user of Qgis, and new on GIS too. I have tried to figure out what is the explanation for what I supposed is something that I am misunderstanding. Using Google Earth I zoomed into a small region and captured the image using print screen. I supposed that Google Earth CRS was WGS 84 (EPSG:4326) for that small area (a city). Now, using Google Maps I selected four specific well and easy referenced points into the image to get geographics coordinates (longitude and latitude). In Qgis Raster/Georeferencer/Georeferencer I added those points once I first added the PNG raster file in this plugin considering that CRS was WGS 84 (EPSG:4326). I saved the points in file.png.points file. In Transformation Setting of this plugin I left the default values, but I selected Create world file and changed the Target SRS to WGS 84 / UTM zone 14N (EPSG:32614). Start georeferencing button produced a world file for PNG image. In a new Qgis session I opened PNG file (with world file present) and Qgis asked me what CRS I wanted to define. If I select WGS 84 / UTM zone 14N I can see how coordinates are changing when I move the mouse over the image, but that coordinates are geographics (longitude and latitude). If I select just WGS 84 (EPSG:4326) then I can see UTM coordinates changes when I move the mouse over the image. But ¡I expected the opposite! Could someone help me to understand this? Regards Gregorio P.S. The CRS of the project is set to WGS 84 / UTM zone 14N (EPSG:32614)Ubuntu 12.04 64bits QGIS version 1.8.0-Lisboa QGIS code revision exported Compiled against Qt 4.8.1 Running against Qt 4.8.1 Compiled against GDAL/OGR 1.7.3 Running against GDAL/OGR 1.7.3 GEOS Version 3.2.2 PostgreSQL Client Version 9.1.4 SpatiaLite Version 3.0.0-beta QWT Version 5.2.2 _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
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