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I needed to load a shape in GRASS GIS to use the v.clean.snap function. The .shp was first viewed in QGIS, projected in 3857 or 4326, I don't remeber. After the adjustments in GRASS GIS I exported to shape. Now when I load the corrected version of my shape in QGIS my features are not in europe but in afrika and whatever CRS I pick it is never right. Did I mess up my file in GRASS? How can I correct that?

The dataset is this one: http://www.unece.org/transport/areas-of-work/transport-statistics/statistics-and-data-online/e-roads/transmainwp6e-roads-census-2005.html

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Overall GRASS is very particular about CRS definitions. It makes no difference how the data was viewed/projected in QGIS. What is important is the original CRS of the shapefile itself. This is included in the *.prj file that should be available along the the *.shp, *.shx and *.dbf.

If the *.prj is there, then you should create a new GRASS Location that exactly matches the CRS of that shapefile (as defined in the *.prj), then import into GRASS, do your processing and export back to a new shapefile.

If the *.prj is not there, then you need to check with the data provider to get the actual projection information.

  • The linked data has .prj files stating a Clarke_1866_Polyconic projection, so you may need to put up a custom CRS for that. – AndreJ Dec 12 '17 at 6:55

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