R: Perform Delaunay triangulation

triangulate {RGeostats}

R Documentation

Perform Delaunay triangulation

Description

Perform Delaunay triangulation

Usage

triangulate(db, triswitch = "qQ", dbaux=NA, gext=NA, segments=NA,
            opt.aux=0, verbose = FALSE, flag.plot=TRUE, flag.data=TRUE, ...)

Arguments

`db`	The `db-class` which contains the vertices to be triangulated.
`triswitch`	Command line which may contain the following kkeywords: p Triangulates a Planar Straight Line Graph. r Refines a previously generated mesh. q Quality mesh generation. A minimum angle may be specified. a Applies a maximum triangle area constraint. u Applies a user-defined triangle constraint. A Applies attributes to identify triangles in certain regions. c Encloses the convex hull with segments. D Conforming Delaunay: all triangles are truly Delaunay. j Jettison unused vertices from output .node file. e Generates an edge list. v Generates a Voronoi diagram. n Generates a list of triangle neighbors. g Generates an .off file for Geomview. B Suppresses output of boundary information. P Suppresses output of .poly file. N Suppresses output of .node file. E Suppresses output of .ele file. I Suppresses mesh iteration numbers. O Ignores holes in .poly file. X Suppresses use of exact arithmetic. z Numbers all items starting from zero (rather than one). o2 Generates second-order subparametric elements. Y Suppresses boundary segment splitting. S Specifies maximum number of added Steiner points. l Uses vertical cuts only, rather than alternating cuts. s Force segments into mesh by splitting (instead of using CDT). C Check consistency of final mesh. Q Quiet: No terminal output except errors. V Verbose: Detailed information on what I'm doing. h Help: Detailed instructions for Triangle.
`dbaux`	Auxilary Db to be taken into account for triangulation.
`gext`	When 'dbaux' is organized as a grid, it may be dilated by gext. This argument designates an array, with its dimension equal to the dimension of the space and which contains the extension defined in number of grid nodes.
`opt.aux`	Option for taking the arguments 'dbaux' and 'gext' into account. 0 The argument 'dbaux' is not used 1 'dbaux' is added to the triangulation 2 'dbaux' extended by 'gext' is added to the triangulation 3 'gext' is added to the triangulation The use of 'gext' is limited to the case wher 'dbaux' is organized as a grid.
`segments`	Array containing some predefined segments (if any).
`verbose`	Verbose flag
`flag.plot`	When TRUE, the constraining vertices, holes and segments are represented. The created trinagles are also represented.
`flag.data`	When TRUE, the data points are overlaid.
`...`	Arguments passed for graphic function such as `triangle.plot`.

Value

A list with the following contents:

npoint.ndim Number of coordinates in Point description
npoint.mark Number of markers in Point description
npoint.natt Number of attributes in Point description
points Matrix of Points. Dimension: number of Points [nrow] * (npoint.ndim + npoint.mark + npoint.natt) [ncol]
nseg.ndim Number of coordinates in Segment description
nseg.mark Number of markers in Segment description
segments Matrix of Segments. Each Segment is defined by the ranks of the two end Points. Dimension: number of Segments [nrow] * (nseg.ndim + nseg.mark) [ncol]
holes Matrix of holes. Dimension: number of holes [nrow] * 2 [ncol]
ntri.ndim Number of coordinates in Triangle description
ntri.natt Number of attributes in Triangle description
ntri.area Number of areas in Triangle description
triangles Matrix of Triangles. Each Triangle is defined by the ranks of the three corner Points. Dimension: number of triangles [nrow] * (ntri.ndim + ntri.natt + ntri.area) [ncol]
neigh Matrix of neighborhood. Each Triangle neighborhood is defined by the ranks of the three neighboring Triangles (-1 if not defined for triangle on the edge of the area). Dimension: number of triangles [nrow] * 3.

Examples

# Load the Data Set from Jonathan Richard Shewchuk web site.
rg.load("Demo.double.hex.db","tri.db")
rg.load("Demo.double.hex.seg","tri.seg")

# Perform the basic triangulation #
res = triangulate(db=tri.db,seg=tri.seg,triswitch="pQ")

# Perform the triangulation with angle constraint #
res = triangulate(db=tri.db,seg=tri.seg,triswitch="QY a0.5")

# Remove file
rm(tri.db, tri.seg, res)

[Package RGeostats version 11.0.4 Index]