How to improve the estimated foliage overlay

This how-to assumes you have followed the previous how-to on how to estimate foliage height using an Infrared WMS Overlay. The how-to ends with a combo overlay that estimates the foliage height based on infra red images, a color filtering overlay and the subtraction of the surface and terrain height overlays. The resulting overlay provided a reasonable height for the tree trunks, but less for the branches of the trees. This how-to tries to improve the estimated foliage.

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

How to improve the estimated foliage overlay:

1. Hover over Overlays in the ribbon bar, and under Grid Calculation select Average and Interpolation.
2. In the Average Overlay's detail panel, click on the Configuration Wizard button.
3. In the Operator step of the wizard, select the MAX option.
4. In the Type step select Input based on an other Grid Overlay.
5. In the Overlay step select the Custom Foliage Height overlay that we created using the previous how-to.
6. Select finish to close the wizard.
7. In the Average Overlay's detail panel, select the Cell averaging distance field and provide the value '12'.
8. Click on the update now button to calculate the Average Overlay.
9. Hover over Overlays in the ribbon bar, and under Grid Calculation, select Combo.
10. In the combo Overlay's detail panel, select the name field and name it Improved Foliage Height.
11. Select the combo box for Grid Input A and select the Custom Foliage Height Overlay.
12. Select the combo box for Grid Input B and select the Average Value Overlay.
13. Select the formula field and type the following formula: IF(GT (A, 0) , B , 0).
14. Select the update now link to calculate the Improved Foliage Height.

{{gallery File:how_to_custom_foliage_height.jpg|Estimated foliage height. File:how_to_improved_foliage_height.jpg|Improved estimated foliage height. }}

Notes

• The average distance of 12 meters is not set in stone, alternative average distances can be used.

How-to's

• How to use a Infrared WMS to estimate foliage height

See also

• WMS Overlay
• Heat Overlay