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In ArcGIS I used to create DEMs from contours with ease. However, we recently opted to stop using ArcGIS (for various reasons), and switching to QGIS.

The reason I use contour data is it is all that is available to me from our surveyor general (20m contour lines).

How can I convert them into DEMs?

There is no step by step GUI tut for GRASS on the matter, GDAL only uses point data, and IDW Interpolation does not produce a good quality DEM either.

PolyGeo
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KeiserZA
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    Welcome to GIS Stack Exchange. Please do a search of this site before asking a question as it will often have been asked before - in this case about three or four times. – MappaGnosis Aug 23 '17 at 07:44

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There is indeed a nice overview page available here:

https://grasswiki.osgeo.org/wiki/Contour_lines_to_DEM

The Wiki page demonstrates and compares a number of different methods of converting vector contour lines into raster DEM surfaces. This includes a series of graphical examples of the output to be expected.

markusN
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  • I have tried it - but my DEM comes out black :( – KeiserZA Aug 23 '17 at 08:10
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    From my understanding if first need to convert the vector files to raster - using v.to.rast.attribute, which i then select the vector file (for the contour) in the source dropdown, chance the attribute to the altitude/height column attribute, regional extent i select the area i want using the canvas select tool, regional cellsize i leave default, brows where to store, and then run - and it comes out black. – KeiserZA Aug 23 '17 at 08:31