Combo Overlay with masking: Difference between revisions

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{{being updated}}
This page describes a use case for implementing a [[Combo Overlay|combo overlay]].
This page describes a use case for implementing a [[Combo Overlay|combo overlay]].


==Use Case Description==
==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?
How can I 'mask' (filter out) all values of a rainfall overlay that is not of the highest range? In this case we use the default highest range of 50 cm or more.


For this we need to create three [[Average Overlay|average grid overlays]], one for each location. Each location needs to have an identifying attribute assigned to it. Then we need to combine these three overlays in a new combo overlay, linking all three average overlays with a logical formula.
For this we need to add a [[Rainfall Overlay|rainfall overlay]] and a formula we can use to mask the values that are too low.


<gallery>
<gallery>
Image:FOO-attr-avg-1.jpg|Average Overlay Clinic
Image:Rainfall_Overlay1.jpg|Rainfall overlay
Image:BAR-attr-avg-1.jpg|Average Overlay School
Image:Combo_Overlay_with_masking1a.jpg|Combo Overlay with masking
Image:BOO-attr-avg-1.jpg|Average Overlay Sports center
Image:Combo_Overlay_with_features1.jpg|Combo Overlay with features
</gallery>
</gallery>


==Formula==
==Formula==


As we want to indicate the and combine the area that is within the range of all three buildings, the formula for the use case, based on the [[Combo Overlay#Operators|operators table]] on the combo overlay page, looks like this:
We want to only show the highest rainfall values, so we want to use all values that are greater then 49 cm (0,049m), and only of the last timeframe (25 in this case). Using  the [[Combo Overlay#Operators|operators table]], this gives us the following formula:


<code>MIN(A, B, C)</code>
<code>MUL(GTE(A25, 0.049), A25)</code>


Where A, B and C are the average grid overlays.
Where <code>A25</code> is the last time frame of the rainfall overlay.


==How to==
==How to==


{{Editor steps|title=add a Combo Overlay with features|Give each building or area you want to include a specific attribute (ex: 'FOO', 'BAR', 'BOO',...)|Create three Average Overlays, set the cell averaging distance to the desired range|Add a Combo Overlay and select the Average overlays in each slot (A,B and C)|Enter the formula in the Formula field|Select 'Update Now' in case auto-update was disabled}}
{{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>
<gallery>
Image:Add_Attr-1.jpg|Select Distance Sight Overlay
Image:Rainfall_Overlay1.jpg|Add a rainfall overlay
Image:Create_Avg_Overlay1.jpg|Select Legend tab
Image:Select_Rainfall_overlays_in_slot1.jpg|Select the rainfall overlays in slot A
Image:Select_AVG_overlays_in_slot1.jpg|Select "Has Custom Legend"
Image:Enter_formula_in_field2.jpg|Enter the formula in the Formula field
Image:Enter_formula_in_field1.jpg|Add new entry
image:Custom_legend_combo_with_features2.jpg|Adjust a custom legend
Image:Select_Update_Now1.jpg|Edit the name, value and color of the entry
Image:Select_Update_Now2.jpg|Select 'Update Now'
</gallery>
</gallery>
{{clear}}
{{clear}}

Latest revision as of 08:35, 10 December 2020

Please note: This page is currently being updated.


This page describes a use case for implementing a combo overlay.

Use Case Description

How can I 'mask' (filter out) all values of a rainfall overlay that is not of the highest range? In this case we use the default highest range of 50 cm or more.

For this we need to add a rainfall overlay and a formula we can use to mask the values that are too low.

Formula

We want to only show the highest rainfall values, so we want to use all values that are greater then 49 cm (0,049m), and only of the last timeframe (25 in this case). Using the operators table, this gives us the following formula:

MUL(GTE(A25, 0.049), A25)

Where A25 is the last time frame of the rainfall overlay.

How to

How to add a Combo Overlay with masking:
  1. Add a rainfall overlay (give it a significant rain event)
  2. Add a Combo Overlay and select the rainfall overlays in slot A
  3. Enter the formula in the Formula field
  4. Enable and adjust a custom legebnd as desired
  5. Select 'Update Now' in case auto-update was disabled