Package 'rvoronoi'

Delaunay Triangulation

Description

Delaunay Triangulation

Usage

delaunay(x, y, calc_polygons = TRUE, calc_areas = FALSE, calc_segments = FALSE)

Arguments

x, y	coordinates of seed sites. Duplicate points are not allowed.
calc_polygons	calculate polygon coordinates default: TRUE
calc_areas	calculate the areas of each triangle. Default: FALSE
calc_segments	calculate segments. Default: FALSE

Value

named list of data

sites

coordinates of sites

ntris

Number of triangles in this delaunay triangulation

tris

data.frame. Each row specifies the indices of the three sites which define a single delaunay triangle. If calc_areas = TRUE then this data.frame also includes an area column

polygons

data.frame of polygon coordinates with x,y and polygon index. Only calculated when calc_polygons = TRUE

segments

The end-points and length of each unique undirected edge in the triangulation. Only calculated when calc_segments = TRUE

v1,v2

vertex indices referencing the original sites

x1,y1,x2,y2

coordinates of ends of segment

len

length of this segment

Examples

set.seed(1)
x <- runif(10)
y <- runif(10)
del <- delaunay(x, y)
plot(del)
del

---

Simple plot of Delaunay triangulation

Description

Simple plot of Delaunay triangulation

Usage

## S3 method for class 'del'
plot(
  x,
  sites = TRUE,
  tris = TRUE,
  segments = FALSE,
  site_pch = 19,
  site_col = "black",
  segment_col = "black",
  tri_col = rainbow(x$ntris),
  ...
)

Arguments

x	output from delaunay()
sites, tris, segments	logical. draw geometric feature
site_pch, site_col	graphics parameters for each input site
segment_col	colour for segments (length = 1)
tri_col	colour for polygons (length = 1 or N)
...	other arguments passed to plot()

Value

None

---

Plot a Voronoi tessellation

Description

Barebones plotting of Voronoi

Usage

## S3 method for class 'vor'
plot(
  x,
  sites = TRUE,
  labels = !sites,
  verts = TRUE,
  polys = TRUE,
  fsegs = !polys,
  isegs = !polys,
  bounds = TRUE,
  site_pch = ".",
  site_cex = 1,
  site_col = "black",
  vert_pch = 19,
  vert_cex = 0.3,
  vert_col = "black",
  label_cex = 0.5,
  fseg_col = "black",
  iseg_col = "red",
  poly_col = rainbow(vor$polygons$npolygons),
  buffer = 0,
  ...
)

Arguments

x	object returned by voronoi()
sites, labels, verts, polys, fsegs, isegs, bounds	logical values. Should this geometric feature be plotted? Default: TRUE
site_pch, site_cex, site_col	parameters for sites
vert_pch, vert_cex, vert_col	parameters for Voronoi vertices
label_cex	size of text labels for sites
fseg_col, iseg_col	colours for finite and infinite segments
poly_col	vector of colours for polygons
buffer	buffer around extents. default: 0
...	other arguments passed to plot()

Value

None.

---

Voronoi Tessellation

Description

Voronoi Tessellation

Usage

voronoi(
  x,
  y,
  calc_polygons = TRUE,
  match_sites = TRUE,
  bound_segments = TRUE,
  merge_tolerance = 1e-10
)

Arguments

x, y	coordinates of seed sites. Duplicate points are not allowed.
calc_polygons	Logical. Should voronoi polygons be calculated? Default: TRUE
match_sites	Logical. Should the polygons be re-ordered to match the seed points? Default: TRUE. This option only makes sense when calc_polygons = TRUE.
bound_segments	logical. Default: TRUE. If calc_polygons = TRUE then this option is always TRUE.
merge_tolerance	Limit of how close the ends of a segment must be before the segment is collapsed to a single vertex Default: 1e-10

Value

An object of class "vor" which is a named list of data.frames.

sites

data.frame of original sites

vertices

data.frame of voronoi vertices. This is the raw output from Fortune's algorithm

segments

data.frame of segments defined by 'line', 'v1' and 'v2'. 'line' is the row index into the 'lines' data.frame. 'v1' and 'v2' are the indices into 'vertices' which define the endpoints along the specified 'line'. If 'v1' or 'v2' are NA this indicates that the segment continues to infinity

polygons

polygon information for each voronoi cell. Only calculated when calc_polygons = TRUE

npolygons

Number of polygons

coords

data.frame of x,y coordiantes and polygon index for all polygons

bbox

data.frame of polygon bounding box information. Each row represents a polygon

centrois

data.frame of polygon centroids. Each row represents a polygon

lines

data.frame of line equations in the voronoi diagram of the form 'ax + by = c'

extents

list of (xmin, ymin), (xmax, ymax) bounding box which encompasses all input sites and voronoi vertices

mvertices

Merged and bounded vertices used to calculate polygons

msegments

Merged and bounded segments used to calculate polygons

Examples

set.seed(1)
x <- runif(10)
y <- runif(10)
vor <- voronoi(x, y)
plot(vor)
vor

---