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.
{{Overlay attribute
==Foliage Crown Factor==
|attribute=FOLIAGE_CROWN_FACTOR
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.
|unit=ratio
|functionvalue=Foliage crown factor
|description=The ratio between the height of tree trunks and the radius of the foliage of the tree.
}}


[[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 construction multiplied by the the crown factor yields the radius of the foliage.
 
The crown factor is used because the extend of foliage itself is not consistently available as geographical data in [[geo-services for land]] use. Instead, only the extent of tree trunks may be recorded.


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

Revision as of 09:33, 20 December 2019

Template:Overlay attribute

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 construction multiplied by the the crown factor yields the radius of the foliage.

The crown factor is used because the extend of foliage itself is not consistently available as geographical data in geo-services for land use. Instead, only the extent of tree trunks may be recorded.

How to

See also

Foliage height calculation model

Notes

When configuring the Heat Overlay, different sources can be selected to define the Foliage height:

  • Buildings with functions related to foliage. The 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.