new-generics {rgeos}
Generics/Methods for polygon objects
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 amountxscaleandyscale, 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)
Documentation reproduced from package rgeos, version 0.2-17. License: GPL (>= 2)