Combo Overlay with distance filtering: Difference between revisions
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Image:Combo_Distance_Filtering1.jpg|Combo Overlay with distance filtering | Image:Combo_Distance_Filtering1.jpg|Combo Overlay with distance filtering | ||
</gallery> | </gallery> | ||
==Formula== | |||
Using the [[Combo Overlay#Operators|operators table]], this gives us the following formula: | |||
<code>MUL(OR(GT(A, 0.1), GT(B, 0.1)), C25)</code> | |||
Where <code>C25</code> is the last time frame of the rainfall overlay. | |||
==How to== | |||
{{Editor steps|title=add a Combo Overlay with masking|Add a rainfall overlay (give it a significant rain event)|Add a Combo Overlay and select the rainfall overlays in slot A|Enter the formula in the Formula field|Enable and adjust a custom legebnd as desired|Select 'Update Now' in case auto-update was disabled}} | |||
<gallery> | |||
Image:Rainfall_Overlay1.jpg|Add a rainfall overlay | |||
Image:Select_Rainfall_overlays_in_slot1.jpg|Select the rainfall overlays in slot A | |||
Image:Enter_formula_in_field2.jpg|Enter the formula in the Formula field | |||
image:Custom_legend_combo_with_features2.jpg|Adjust a custom legend | |||
Image:Select_Update_Now2.jpg|Select 'Update Now' | |||
</gallery> | |||
{{clear}} |
Revision as of 16:03, 8 December 2020
This page describes a use case for implementing a combo overlay.
Use Case Description
In an area, the locations for social and normal housing are known. Where does severe rainfall (50cm or higher) have impact on social and normal housing?
For this we need to create two average grid overlays, one for social housing and one for normal housing, by selecting the respective category wieght attributes; SOCIAL_CATEGORY_WEIGHT and NORMAL_CATEGORY_WEIGHT. Give each overlay a cell averaging distance of 30m. We also need to add a rainfall overlay to have as a 'filter' over the combination of the other two overlays.
Formula
Using the operators table, this gives us the following formula:
MUL(OR(GT(A, 0.1), GT(B, 0.1)), C25)
Where C25
is the last time frame of the rainfall overlay.
How to
- Add a rainfall overlay (give it a significant rain event)
- Add a Combo Overlay and select the rainfall overlays in slot A
- Enter the formula in the Formula field
- Enable and adjust a custom legebnd as desired
- Select 'Update Now' in case auto-update was disabled