Class: Patches

The patches object provides functions to create and manage spatial sub-divisions (patches) within a forest stand. Patches are defined on a 10x10m grid. They can be used for spatially explicit forest management.

Use the patches property of the (current) stand variable to access the functionality.

 // create 2 random patches
 stand.patches.createRandomPatches(2);
 // get the list of patches
 var patch_list = stand.patches.list;
 // get the light influence field for the first patch
 log("LIF of first patch: " + stand.patches.lif(patch_list[0]));

Properties Overview

Name Type Description
list Array A list containing all Patch objects of the current stand.
rectangle Object The bounding rectangle of the stand in meters. This is a read-only property.

Methods Overview

Method Return Type Description
clear() void Removes all existing patches from the stand.
createExtendedPatch(patchId, newPatchId) integer Creates a new patch by extending an existing patch.
createFromGrid(grid) Array Creates patches from a raster grid. The grid is provided as a ScriptGrid object.
createPatch(x, y, shape_string) boolean Creates a single patch with a specific shape at a given location.
createRandomPatches(n) void Creates a given number of random patches within the stand.
createRegular(size, spacing) Array Creates a regular pattern of patches (e.g., squares).
createStrips(width, horizontal) Array Creates patches in the form of horizontal or vertical strips.
lif(patch) double Calculates the average value of the Light Influence Field (LIF) at 4m height for a given patch.
updateGrid() void This method is usually called automatically. It re-creates the internal 10x10m grid representation

Properties Details

list

Array

A list containing all Patch objects of the current stand.

rectangle

Object

The bounding rectangle of the stand in meters. This is a read-only property. The rectangle object has x, y, width, and height properties.

Methods Details

clear()

Returns: void

Removes all existing patches from the stand.

createExtendedPatch(patchId, newPatchId)

Returns: integer

Creates a new patch by extending an existing patch. The new patch surrounds the existing patch with the given patchId.

Parameters:

  • patchId (integer): The ID of the existing patch to extend.
  • newPatchId (integer): The ID for the new patch.

Return Value Description: The number of cells added to the new patch.

createFromGrid(grid)

Returns: Array

Creates patches from a raster grid. The grid is provided as a ScriptGrid object. For each unique value in the grid, a corresponding patch is created.

Parameters:

  • grid (ScriptGrid): The input grid object.

Return Value Description: A list of the created Patch objects.

createPatch(x, y, shape_string)

Returns: boolean

Creates a single patch with a specific shape at a given location.

Parameters:

  • x (double): The x-coordinate (in meters) of the center of the shape.
  • y (double): The y-coordinate (in meters) of the center of the shape.
  • shape_string (string): A string defining the shape, e.g., “circle(15)” for a circle with a 15m radius, or “rect(20,30)” for a 20x30m rectangle.

Return Value Description: true if the patch was created successfully, false otherwise.

createRandomPatches(n)

Returns: void

Creates a given number of random patches within the stand. The patches are non-overlapping and cover the entire stand area.

Parameters:

  • n (integer): The number of random patches to create.

createRegular(size, spacing)

Returns: Array

Creates a regular pattern of patches (e.g., squares).

Parameters:

  • size (integer): The size of each patch in meters.
  • spacing (integer): The spacing between patches in meters.

Return Value Description: A list of the created Patch objects.

createStrips(width, horizontal)

Returns: Array

Creates patches in the form of horizontal or vertical strips.

Parameters:

  • width (double): The width of the strips in meters.
  • horizontal (boolean): If true, horizontal strips are created, otherwise vertical strips.

Return Value Description: A list of the created Patch objects.

lif(patch)

Returns: double

Calculates the average value of the Light Influence Field (LIF) at 4m height for a given patch.

Parameters:

  • patch (Patch): The patch object for which to calculate the average LIF.

Return Value Description: The average LIF value for the patch.

updateGrid()

Returns: void

This method is usually called automatically. It re-creates the internal 10x10m grid representation of the patches from the list of patch objects. You might need to call this if you have manipulated the list of patches manually.