I'm trying to follow the set of instructions here: https://twitter.com/imhere_asia/status/1023055838787690496
[EDIT] Pasting the instructions here for reference so people can avoid twitter.
- Add a DEM raster into your project
- Open the processing panel, and select the "Create grid" algorithm
- You'll want to create a point grid, with narrow horizontal spacing (roughly matching the cell size of you DEM raster) and larger vertical spacing)
- Select the "Translate" algorithm
- Use the above-created point grid as your input layer
- The magic happens here: set the y-axis offset distance value to be the following data-defined expression: "raster_value('dem_layer',1,$geometry)
- Run the algorithm
- Lastly, select the "Points to path" algorithm
- Use the above-created translated layer as input layer
- Use the "left" field as order field and "top" field as group field
- Run the algorithm, et voila.
The end goal of this is to end up with a map corresponding to the DEM that looks sort of like the classic joy division cover (see image above from twitter). The spot where I'm getting stuck is step 6.
However, when I translate the grid by
raster_value('my_dem',1,$geometry), the algorithm runs, but the new layer is identical. The dem layer is an SRTM GeoTIFF. What am I doing wrong?