buffer: Identify the buffer zone in the point pattern

In Zongzheng/forestSAS: An R package for forest spatial structure analysis systems

Description

To eliminate edge effects and improve the accuracy of the Calculation,such as analyzing the forest spatial structure parameters, we always established a buffer zone around the plot. In the statistical analysis, only the trees in the reduced window are used as reference trees, and the individual trees in the buffer zone are only considered to be the nearest neighbors of the trees in the reduced window. This edge correction can individually evaluate each tree to determine whether all n nearest neighbors are truly located within the plot.

Usage

buffer(X, buf.xwid = 5, buf.ywid = 5)

Arguments

X	A point pattern (object of class "ppp").
buf.xwid	The width of buffer zone in the x coordinates of data points
buf.ywid	The width of buffer zone in the y coordinates of data points

Value

An object of class "ppp", which add a marks "zone" in the orginal point pattern

Author(s)

Zongzheng Chai, [e-mail]

References

Chai ZZ, Sun CL, Wang DX, Liu WZ, and Zhang CS.2016. Spatial structure and dynamics of predominant populations in a virgin old-growthoak forest in the Qinling Mountains, China. Scandinavian Journal of Forest Research. DOI: 10.1080/02827581.2016.1183703

Examples

library(spatstat)
####Based on the simulated data####
# Creating a simulated point pattern
x <- runif(20)
y <- runif(20)
X <- ppp(x, y, c(0,1), c(0,1))
X
# Identifing the buffer zone and core zone in the point pattern
# The width of buffer zone in the x coordinates of data points is 0.2
# The width of buffer zone in the y coordinates of data points is 0.3
X_buf<-buffer(X,buf.xwid =0.2,buf.ywid=0.3)
X_buf
as.data.frame(X_buf)

####Based on the example data####
data(finpines)
finpines
# Marked planar point pattern: 126 points
# Mark variables: diameter, height
# window: rectangle = [-5, 5] x [-8, 2] metres

# Identifing the buffer zone and core zone in the finpines
# The width of buffer zone in the x coordinates of finpines is 2
# The width of buffer zone in the y coordinates of finpines is 3
finpines_buf<-buffer(finpines,buf.xwid =2,buf.ywid=3)
finpines_buf
as.data.frame(finpines_buf)

Zongzheng/forestSAS documentation built on May 10, 2019, 1:59 a.m.