rowcol.to.index {CTFS} | R Documentation

## Converts a Row and Column to a Quadrate Number

### Description

This functions takes row and column numbers and identifies the quadrate number (index). The row and column numbers are based on a gridsize that by default divides the plot into 20 by 20 m squares. The gridsize can be defined by the user so other quadrate sizes can be used.

### Usage

    rowcol.to.index(rowno, colno, gridsize = 20, plotdim = c(1000, 500))

### Arguments

`rowno` | row number, range from 1 to 25 for default plot
`colno` | column number, range from 1 to 50 for default plot
`gridsize` | side of the square quadrate, 20 x 20m by default
`plotdim` | dimensions of the plot: east-west 1000m and north-south 500m

### Details

The function should work for any 4 sided plot, square or rectangular. The convention is 20 by 20 m quadrates, 1250 of them in a 1000 by 500 m plot. The convention is to number the quadrates starting in the southwest corner and going northward up a "column" of 25, and returning to the southern border for 26-50, etc. The columns are numbered 1 to 50, west to east (left to right). The rows are numbered 1 to 25, south to north (bottom to top).

### Value

Returns a vector, the index number of the quadrate (default values range from 1 to 1250). Returns NA when invalid row or column number is provided.

### Author(s)

Rick Condit, Suzanne Lao and Pamela Hall

### See Also

`CTFS.quadfunctions`

### Examples

    ## Not run:

    rowcol.to.index(21,43)

    # out of bounds
    rowcol.to.index(26,39)

    The 4 corner quadrates

    tstrow=c(1,25,1,25)
    tstcol=c(1,1,50,50)
    rowcol.to.index(tstrow,tstcol)

    ## End(Not run)

[Package CTFS version 1.00 Index]