Foliage crown factor (Heat Overlay): Difference between revisions

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Knowing where and at what height the foliage is present geographically is an important factor in [[Shade_calculation_model_(Heat_Overlay)|Shade]] and [[Sky_view_factor_calculation_model_(Heat_Overlay)|Skyview]] calculations. Unfortunately, foliage is not always stored as geographical data in Landuse Geo-services. Instead, sometimes only the tree trunks have been recorded. Additionally, when designing new scenario's, foliage for newly added trees cannot be obtained from existing services and must instead be generated by some algorithm. In order to facilitate generating foliage, the foliage crown factor function value has been added.
{{Building attributes
==Foliage Crown Factor==
| <onlyinclude>
The foliage crown factor is a means to determine what areas surrounding tree trunks get covered by the trees' foliage. By multiplying the tree's height with the foliage crown factor one obtains the foliage radius.
{{Building attributes|type=row|group=Heat Overlay
|attribute=FOLIAGE_CROWN_FACTOR
|unit=ratio
|functionvalue=Foliage crown factor
|description=The ratio between the height of tree trunks and the diameter of the foliage of the tree.
|icon=
}} </onlyinclude>}}


[[File:Foliage_trunk.png|400px]][[File:Foliage_crown_factor.png|400px]][[File:Foliage_top.png|400px]]
The foliage crown factor is used to calculate the extend of foliage, which can influence the calculation of the sky view and the shade. The height of the Building multiplied by the the crown factor yields the diameter of the foliage.


==How to==
The crown factor is used because the extend of foliage itself is not generally available as geographical open data. Instead, often only the extent of tree trunks are provided.
* [[How_to_adjust_the_foliage_height_and_crown_factor|How to adjust the foliage height and crown factor]]


==See also==
{{article end
[[Foliage_height_calculation_model_(Heat_Overlay)|Foliage height calculation model]]
|notes=
* Foliage can be [[Foliage height calculation model (Heat Overlay)|calculated]] based on the FOLIAGE_CROWN_FACTOR. This calculation can be superseded when the [[Heat Overlay]] (set to use the [[DPRA Heat Module]]) is configured to use either [[Area]]s or a [[GeoTIFF]] to determine foliage height. In those cases the FOLIAGE_CROWN_FACTOR of [[Building]]s is unused.
|seealso=
* [[Foliage height calculation model (Heat Overlay)]]
* [[Foliage crown factor (Function Value)]]
|howtos=
* [[How to adjust the foliage height and crown factor]]
* [[Trees and foliage tutorial]]
}}


==Notes==
{{HeatOverlay model attribute nav}}
When configuring the Heat Overlay, different sources can be selected to define the Foliage height:
* Buildings with [[Function|functions]] related to foliage. The [[Foliage_height_calculation_model_(Heat_Overlay)|foliage height calculation model]] will determine the foliage height using the height of the vegetation (as buildings) and the foliage crown factor attribute;
* Areas with as foliage height attribute, defining the foliage height for a whole area;
* [[GeoTiff]], defining a foliage height value for each cell in its raster.

Latest revision as of 14:09, 26 January 2024

The foliage crown factor is used to calculate the extend of foliage, which can influence the calculation of the sky view and the shade. The height of the Building multiplied by the the crown factor yields the diameter of the foliage.

The crown factor is used because the extend of foliage itself is not generally available as geographical open data. Instead, often only the extent of tree trunks are provided.

Notes

How-to's

See also