Tract: Generate Objects of Class "`'>Tract`"

Description

This generic function has methods based on the signature formal argument object. It is used as a constructor function for objects that are of class "'>Tract". This method should be used in preference to new to insure a valid object.

Usage

Tract(object, ...)

Arguments

object

This is the signature formal argument, see the methods for more details.

…

Formal arguments that are different for each method, see those for details.

Value

A valid object of class "'>Tract."

Details

There is no default generic function for Tract per se. It is defined completely with respect to the signature of its methods Tract-methods. Methods are available for several useful signatures, such as objects of class "'>RasterLayer", allowing for a large variety of ways to generate objects of this class. Other methods can obviously be added for other signatures as necessary.

Examples

Run this code

# NOT RUN {
tract = Tract(c(x=20,y=20), cellSize=0.25)    #extents constructor
tr = Tract(,0.5, c(x=20,y=20),c(0.25,0.25),units='metric') #missing constructor
tr2 = Tract(cellSize=0.5, cellDims=c(x=20,y=20), cellCenter=c(0.25,0.25),
            units='metric') #same constructor as the previous
tr.ext = Tract(c(x=10,y=15), cellSize=0.5) #maximal extent constructor
#bounding box constructor...
bb = bbox(tr.ext)
bb[,1] = c(5,4)
tr3 = Tract(bb, 0.5)
#RasterLayer constructor...
ex = extent(tr3)
rl = raster(ex, nrow=10, ncols=10, crs=NA)
# }
# NOT RUN {
tr4 = Tract(rl)  #error: non-square grid cells
# }
# NOT RUN {
rl = raster(ex, nrow=22, ncol=10, crs=NA)
tr4 = Tract(rl)  #okay, square cells
# }