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new-generics {rgeos}

Generics/Methods for polygon objects
Package: 
rgeos
Version: 
0.3-3

Description

Some generic functions and methods for polygon objects

Usage

append.poly(x, y)
area.poly(object, ...)
get.pts(object)
get.bbox(x)
scale.poly(x, ...)
tristrip(x)
triangulate(x)

Arguments

x,object
A polygon object
y
A polygon object
...
Other arguments passed to methods

Details

The result of tristrip(x) is a list of two-column matrices. Each matrix is a tristrip, i.e. the rows are vertices of triangles, with each overlapping triple of rows corresponding to a separate triangle.

The result of triangulate(x) is a single two-column matrix. The rows are vertices of triangles, taken in non-overlapping triples.

Methods

append.poly
signature(x = "gpc.poly", y =     "gpc.poly"): Combine all contours of two "gpc.poly" objects and return the combined polygon as a "gpc.poly" object.
area.poly
signature(object = "gpc.poly"): Compute and return the sum of the areas of all contours in a "gpc.poly" object.
scale.poly
signature(x = "gpc.poly"): Scale (divide) the x and y coordinates of a "gpc.poly" object by the amount xscale and yscale, respectively. Return a scaled "gpc.poly" object.
get.pts
signature(object = "gpc.poly"): Return the list of x and y coordinates of the vertices of a "gpc.poly" object.
get.bbox
signature(x = "gpc.poly"): Return the bounding box for a "gpc.poly" object.
tristrip
signature(x = "gpc.poly"): Return a tristrip list for a "gpc.poly" object.
triangulate
signature(x = "gpc.poly"): Return a matrix of vertices of a triangulation of a "gpc.poly" object.

See Also

"gpc.poly" class documentation.

Examples

holepoly <- read.polyfile(system.file("poly-ex-gpc/hole-poly.txt",
 package ="rgeos"), nohole = FALSE)
area.poly(holepoly)
stopifnot(area.poly(holepoly) == 8)

Author(s)

Roger D. Peng; GPC Library by Alan Murta; tristrip additions by Duncan Murdoch

Documentation reproduced from package rgeos, version 0.3-3. License: GPL (>= 2)