Creating DEM Contour files from shapefile line data in QGIS

Question

There are many question occurring on this forum regarding this issue, however the issue I am facing has not been answered in Generating DEM from contour Shapefile using QGIS?, which is that I have contour line data. Not point data.

Following the steps in Generating DEM from contour Shapefile using QGIS?. I have used SAGA Tool in the Processing Toolbox. Selected the Triangulation Tool from the Raster Creation Tools.

At this point It asks for the 'points' required for rasterising. But I want to input 'line data' does anyone know how to do this?

below shows the 'line data expressed in QGIS'

the purpose behind this is due to the fact I need to create a 'height profile' using the Profile tool to create a cross section area from contours as seen in the example below.

I am using QGIS V 3.4

Answer 1

I had the same question and looked everywhere! Finally a solution - you need to use "TIN interpolation". This video explains it perfectly: https://www.youtube.com/watch?v=PhJ77uHlTJA

It demonstrates other processes as well but the main thing is they used contour line data and created a DEM. Really good explanation as well.

Key tools used:

• TIN interpolation (Processing Toolbox)
• Slope (you can skip this one) (Processing Toolbox)
• Hillshade (Raster tab)

Answer 2

This can be done using the

MMQGIS plugin

Once added it will show up in the tool bar at the top of the screen. Select/highland the 'line.data' layer you want to convert to 'points.data'. click on MMQGIS and a drop down will appear. Then click on Modify and then Convert Geometry Type

Then a box appears as seen below -->

Change the 'New Geometry Type' to nodes from default 'line centers' and save the output file. Once ready click apply and this will change line data to point data