areaProportion: This function is to derive a correction index to account for...

In bcgov/FAIBBase: Basic functions for forest mensuration and ecology

This function is to derive a correction index to account for edge effect when account for competition effect

Description

The correction index is calculated using proportion of overlapped area to full circular area.

Usage

areaProportion(
  bearing,
  distance,
  radius,
  baseShape = "circle",
  baseRadius = 10,
  baseCorners = list(c(-50, 50), c(50, 50), c(50, -50), c(-50, -50))
)

Arguments

bearing	numeric, The bearing of a tree from a given point of plot (centre or corner).
distance	numeric, The distance of a tree from a given point of plot (centre or corner).
radius	numeric, The radius for a focal subject, which define the circular area around a subject tree.
baseShape	character, The shape of the area to be overlapped. Must be either circle or rectangle. Default is circle.
baseRadius	numeric, The radius for the base area, if the shape is defined as circle. Default is 10.
baseCorners	list, If the shape is defined as rectangle, this argument specifies upper left, upper right, lower right and lower left corners. Default is list(c(-50, 50), c(50, 50), c(50, -50), c(-50, -50)), which represent a 10000 m2 base area.

Value

A ratio of overlapped area to full circular area.

Author(s)

Yong Luo

Examples

## Not run: 
# given a tree is located with bearing of 150 degree and distance of 13 m
# and in a plot of 16.9 m radius circle, in which all the trees are measured.
# assume all the trees within 10m radius have competitive effect on this tree
# hence the trees that are in the plot and within 10m radius from focal tree
# should be corrected based on proportion
# to calculate the proportion
proportion <- areaProportion(bearing = 150,
                             distance = 13,
                             radius = 10,
                             baseShape = "circle",
                             baseRadius = 16.9)




## End(Not run)

bcgov/FAIBBase documentation built on June 19, 2024, 11:57 p.m.