Solar Radiation: free method

This is a follow-up post to Tuesday’s Garden Placement Using Publicly Available LiDAR, which relied on ArcGIS’ Spatial Analyst extension. Huge hat tip to the LAStools Linkedin conversation, and particularly Daniel Grohmann, for mentioning the freely available SAGA GIS tool, Potential Incoming Solar Radiation. I should note that this is truly my first attempt at using SAGA, so apologies in advance if I’m leading you astray in some way.

To recap, we had created a digital elevation model (DEM) from publicly available LiDAR from the City of Prince George, and were ready to calculate solar radiation values for a city block in order to optimally locate a garden plot.

  1. Download, install, and open SAGA GIS (it’s free)
  2. Import your DEM into SAGA. I used the GDAL: Import Raster module (Modules -> File -> GDAL/OGR -> GDAL: Import Raster). Double-click the layer in the Data workspace window to view the raster and ensure it imported correctly.
  3. Open the Potential Incoming Solar Radiation tool (Modules -> Terrain Analysis -> Lighting -> Potential Incoming Solar Radiation). Here is how I set up my run:
  4. After changing the colour ramp to the default (blue -> red), we are left with a very similar, if not identical, solar radiation map comapred to that produced by Spatial Analyst:

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