rowcol.to.index {CTFS} | R Documentation |
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.
rowcol.to.index(rowno, colno, gridsize = 20, plotdim = c(1000, 500))
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 |
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).
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.
Rick Condit, Suzanne Lao and Pamela Hall
## 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)