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]