gxgy.to.rowcol {CTFS}R Documentation

Converts a GX GY Coordinates to Row and Column Numbers

Description

This functions takes gx gy tree coordinate position and identifies the row and column numbers in which it is located. 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. The inverse function is rowcol.to.gxgy.

Usage

gxgy.to.rowcol(gx, gy, gridsize = 20, plotdim = c(1000, 500))

Arguments

gx tree x coordinate
gy tree y coordinate
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 data frame of row and column numbers. Returns NA when an invalid gx or gy is given.

Author(s)

Rick Condit, Suzanne Lao and Pamela Hall

See Also

CTFS.quadfunctions

Examples

## Not run: 
tst.gy=c(0,499,0,499)
tst.gx=c(0,0,999,999)
gxgy.to.rowcol(tst.gx,tst.gy)

# the far edges of the plot are out of bounds
tst.gx=c(0,0,1000,1000)
tst.gy=c(0,500,0,500)
gxgy.to.rowcol(tst.gx,tst.gy)
## End(Not run)

[Package CTFS version 1.00 Index]