The relief command generates shaded relief from a Digital Elevation Model (DEM). You can use any DEM in a planar projection, but a resolution of 30 metres or better is suggested.
Use the ELVIS website [http://elevation.fsdf.org.au] to download DEM tiles for any NSW location. The NSW 2-metre and 5-metre tiles are ideal. 1-metre NSW and ACT tiles also work but are more detailed than necessary. (Do not download Geoscience Australia tiles or point-cloud data.)
DEM tiles from the ELVIS website are delivered as doubly-zipped files. It's not necessary to unzip the download, although unzipping the first level to a folder will improve processing time.
No configuration is needed to get good results from ELVIS data. Use the following options to adjust the layer's appearance, if desired:
- resolution: resolution for the DEM data; a lower value will reduce file size but yields a smoother effect
- opacity: overall layer opacity
- altitude: raking angle of the light from the horizon
- factor: vertical exaggeration factor
Opacity and exaggeration can both be used to adjust the subtly of the shading effect.
Use the --epsg option to override the EPSG projection code for the DEM, in case of missing metadata (e.g. ACT 2015 DEM tiles).