select.randquad {CTFS} | R Documentation |
Takes a vector of quadrate sizes and randomly selects a point on
the plot as the initial corner. This function is called by
spp.randarea.range
and is not usually called alone.
select.randquad(quadside, shape = 1, plotdim = c(1000, 500), replicates = 100)
quadside |
vector of dimensions (x) of the randomly selected area in meters |
shape |
single value numeric, factor used to determine dimension y of quadrate. for a square, shape = 1 |
plotdim |
plot dimensions, x,y lengths in meters |
replicates |
number of randomly selected areas to sample |
The dimensions of the selected quadrate are determined by the values
in quadside
and shape
. The quadrate dimensions are
x = quadside[i]
and y = quadside[i]
* shape[i]
.
If one shape
value is provided then it is used for all
quadrates. The returned x and y
coordinates, paired, define the four corners of the quadrates.
xlo |
x coordinate |
ylo |
y coordinate |
xhi |
x coordinate |
yhi |
y coordinate |
area |
area of each quadrate in hectares |
Rick Condit, Suzanne Lao and Pamela Hall
## Not run: 1. There are no defaults for this function, parameters must be supplied. This results in 10 sets of coordinates for 1 hectare, square quadrates. select.randquad(quadside=100,shape=1,replicates=10) 2. Try a rectangular quadrate and quadrates of different shapes select.randquad(quadside=100,shape=2,replicates=10) select.randquad(quadside=100,shape=c(2,3),replicates=10) select.randquad(quadside=c(10,100),shape=1,replicates=10) select.randquad(quadside=c(10,100),shape=c(2,3),replicates=10) ## End(Not run)