How to compute additional shadow effects for the Heat Stress Overlay

For some cases of heat stress, innovative solutions can be explored to reduce the amount of heat experienced during the day. With the most impactful component being the application of shade, it can be useful to add additional effects of shade to a Heat Stress calculation. The way to do this is to effectively inject additional data into the foliage input of the Heat Stress Overlay, which will serve as the main applicator of additional shade. This will require one Heat Stress Overlay to compute the default foliage effects, a Combo Overlay to combine this information with whatever additional shading is to be added, and a second, final Heat Stress Overlay to perform the actual Heat calculation.

The steps described here assume shading can be added either through specific Building Types, or through the existence/activation of Areas.

Editor → Current Situation (Ribbon tab) → Overlays (Ribbon bar)

How to compute additional shadow effects for the Heat Stress Overlay:

1. Ensure the relevant Functions or Areas have an Attribute indicating the presence of shade. (For example: ADDITIONAL_SHADE, with value 1)
2. Ensure a Heat Stress Overlay exists, which will perform the actual calculation.
3. Add an additional Heat Stress Overlay, with its result type in the right panel set to "Foliage".
4. Add an Average Overlay with the following configuration:
   In the right panel, set the layer type to "First Layer".
   In the right panel, set the averaging distance to 0.
   In the right panel, set the Attribute to look at to the Attribute indicating the presence of shade (For example: ADDITIONAL_SHADE).
5. Add a Combo Overlay, with the following configuration:
   In the right panel, set input A to the Heat Stress Overlay configured to output foliage.
   In the right panel, set input B to the Averaging Overlay configured to the Average Overlay.
   In the right panel, set formula to: MAX(A,B)
6. In the left panel, select the Heat Stress Overlay for the actual heat calculation.
7. In the right panel, click on the button for the configuration wizard to open the configuration wizard.
8. In the step regarding foliage, opt to base foliage on a Grid Overlay.
9. As the Grid Overlay to use, select the configured Combo Overlay.
10. Recalculate the Project.

See also

• How to add an Attribute to a Function