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]