findborderquads {CTFS}R Documentation

Returns Indices of Neighboring Quadrats Given a Quadrat Index

Description

Identified neighboring quadrates from a given quadrate number, refered to as the index. Returns the quadrat numbers within a given distance.

Usage

findborderquads(index, dist = 20, gridsize = 20, plotdim = c(1000, 500))

Arguments

index quadrate number, between 0 and 1249 in the standard plot
dist distance in m within which the neighboring quadrates are located. Distance is measured from any side of the index quadrate.
gridsize side of the square quadrate, 20 x 20m by default
plotdim dimensions of the plot: east-west 1000m and north-south 500m

Details

A quadrate is considered a neighbor if any part of it lies within dist of the center of the quadrate indicated by index. At the minimum the quadrates that share edges, including corners, will always be returned. This is 8 quadrates. The index quadrate is NOT returned. All values >=0 and <20 give the same 8 quadrates for a centrally located quadrate.

As dist increases, more quadrates can be included up to the edges of the plot. For gridsize=20, 8 quadrates are neighbors up to dist<20. This doesn't change until dist >= 20, then there are 24 neighbors, etc.

This function depends upon index.to.rowcol to identify the neighboring quadrates.

Value

Returns a vector of numbers, the quadrate indices for all surrounding quadrates.

Author(s)

Rick Condit

See Also

CTFS.quadfunctions

Examples

## Not run: 
sort(findborderquads(231,dist=10))
sort(findborderquads(231,dist=20))
sort(findborderquads(231,dist=0))

## End(Not run)

[Package CTFS version 1.00 Index]