tess: Create a Tessellation

Description

Creates an object of class "tess" representing a tessellation of a spatial region.

Usage

tess(..., xgrid = NULL, ygrid = NULL, tiles = NULL, image = NULL)

Arguments

...

Ignored.

xgrid,ygrid

Cartesian coordinates of vertical and horizontal lines determining a grid of rectangles. Incompatible with other arguments.

tiles

List of tiles in the tessellation. A list, each of whose elements is a window (object of class "owin"). Incompatible with other arguments.

image

Pixel image which specifies the tessellation. Incompatible with other arguments.

Value

An object of class "tess" representing the tessellation.

Details

A tessellation is a collection of disjoint spatial regions (called tiles) that fit together to form a larger spatial region. This command creates an object of class "tess" that represents a tessellation.

Three types of tessellation are supported: [object Object],[object Object],[object Object] There are methods for print, plot, [ and [<- for tessellations. Use tiles to extract the list of tiles in a tessellation.

Tessellations can be used to classify the points of a point pattern, in split.ppp, cut.ppp and by.ppp.

Examples

Run this code

A <- tess(xgrid=0:4,ygrid=0:4)
  A
  B <- A[c(1, 2, 5, 7, 9)]
  B
  v <- as.im(function(x,y){factor(round(5 * (x^2 + y^2)))}, W=owin())
  levels(v) <- letters[seq(length(levels(v)))]
  E <- tess(image=v)
  E

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