View source for Average Overlay

[[File:Average_overlay_example.JPG|thumb|250px|left|The Average Overlay of the urbanization attribute.]]
The Average Overlay is a multi purpose [[Grid overlay|Grid Overlay]] which displays (smoothed) values. These values can originate from 2D spatial objects, such as buildings, terrains, areas or neighborhoods. The values can also originate from an other [[Grid Overlay]].

Another typical use-case of the Average Overlay is to visualize parameters of a simulation model (e.g. the [[Rainfall _(Overlay)|rainfall overlay]]). A parameter assigned to a grid-cell can be related to one or more layers of the 3D model: [[Constructions|Buildings]], [[Address|Addresses]], [[Terrains]], [[Areas]], [[Neighborhoods]] and [[Net Lines]].

Thirdly the Average overlay supports replacing {{nodata}} values with interpolated non {{nodata}} values using surrounding cells within a specified distance.
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==Additional information displayed in hover panel==
[[File:Average_hover_panel.JPG|thumb|250px|right|The Average Overlay of the urbanization attribute and additional information in the hover panel.]]
When clicking on a specific location in the map of the Average Overlay, the hover panel gives additional information over the actual value in that specific grid cell.
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==Calculation==
The Average Overlay works by first computing a grid of input values. This is a 1-on-1 representation of the data found spatially in the [[Project]]. Then, for each [[grid cell]], the values of all cells within a given radius from that one cell are summed up, and divided by the total amount of cells found in that radius. The output value of that one cell is that computed average. 

The Average Overlay can be configured to fine-tune the exact data which should serve as input, and how the calculation should take place.

===Input===
The Average Overlay requires an initial input, which it can then average out over a specified range. The input can be either an [[Attribute]] of vector data, or a [[Grid Overlay]]. The following options are available:
; Attribute First Layer
: Use the first value found among the layers of vector data which have the specified [[Attribute]]. If no such [[Attribute]] exists in a specific location, the used value is 0.

; Attribute Min Layer / Max Layer
: Use either the lowest or the highest value found among the layers of vector data which have the specified [[Attribute]]. If no such [[Attribute]] exists in a specific location, the used value is 0.

; Attribute Specific Layer
: Use the defined [[Attribute]]'s value from the specific layer of vector data specified. Exactly one layer can be specified. If no such [[Attribute]] exists in a specific location, the used value is 0.

; Grid Overlay
: Use the values of another [[Grid Overlay]] when specified as input. No [[Attribute]] needs to be specified. {{nodata}} values of the referenced Overlay result in {{nodata}} values in the grid. The Average Overlay will have [[timeframe]]s equal to the amount of [[timeframe]]s of the Input Overlay. In case the input Grid Overlay does not have the same grid size as the Average Overlay, the input Grid Overlay 's value grid is automatically resized.

===Calculation===
The way of averaging is defined by several [[Attribute]]s, and can most easily be set using the [[How to use the Average Overlay Wizard|Average Overlay Wizard]].

The calculation can be configured via the following attributes:
{{overlay attributes|suppresscategory=true|allowselflinks=true|
  {{:Attribute timeframes (Average Overlay)}}
  {{:Distance m (Average Overlay)}}
  {{:No data interpolation (Average Overlay)}}
}}

{{article end
|notes=
|howtos=
* [[How to use the Average Overlay Wizard]]
* [[How to add and remove an Overlay]]
* [[How to edit an overlay legend]]
|external=
* [https://www.tygron.com/en/idea/extended-combo-and-average-overlay-functionalities  Extended Combo and average overlay functionalities.]
}}

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