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Is it possible to give digitized altitude lines (from paper map) heights using QGIS?

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    Automatically? No. Manually? Yes (add an attribute field to the lines, enter the elevation value from the map). As just an attribute? Yes, see previous sentence. As part of the actual geometry, so you have a 3D line? I think so, but I don't know the tool(s) in QGIS to do it. – Chris W Nov 19 '14 at 22:45
  • You understood this correctly, I want to give the contourlines z-values and I don't know the plugin or tool. You know the name of the tool in ArcGIS? – Jhonstons Nov 20 '14 at 13:17
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    @Jhonstons in ArcGIS, you'd do this using the Feature to 3D By Attribute tool (part of the 3D Analyst extension). That will take a Z-value from an attribute field you specify and use it to convert your features into actual 3D features with those Z-values. I don't know how to do it in QGIS though (if it's possible). – Dan C Nov 20 '14 at 16:45
  • How to do this in ArcGIS is covered at gis.stackexchange.com/questions/53270 and also discussed at gis.stackexchange.com/questions/75497 (which also addresses QGIS), but the answers went a different direction based on the asker's needs. IE, they only needed it as an attribute for what they wanted to do, they didn't need them to be true 3D lines. – Chris W Nov 20 '14 at 20:51
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3D is not (yet) implemented in QGIS, but you can store the height in an attribute table field and create a 3D output manually with ogr2ogr -z_field fieldname outside QGIS.

See Is it possible to create 3D dxf with OGR? for an example.

This is rather 2.5D, because all vertices of a line must have the same elevation (as contours have).

In QGIS, you could use Save As ... and put into the layer creation option field -SHPT=ARCZ according to http://www.gdal.org/drv_shapefile.html , but I don't know how to add the -z_field option there.

  • Thanks for confirming Andre. I kept seeing that QGIS didn't support 3D, but then I'd find things like 3D point and line classes and the fact that it supports shapefiles, which can be 3D geometries (well, xymz). I wasn't sure if it still couldn't/had no tools to work with it like ArcGIS, or if I was just seeing outdated information. – Chris W Nov 20 '14 at 20:44

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