createxymap {BayesX}

Create map objects for some points and a given distance

Description

Creates a map object from a list of coordinates by treating observations within a certain distance as neighbors. The resulting neighborhood structure is stored in a map object in graph format while a map in boundary format is created to enable visualisation.

Usage

createxymap(x, y, districts=NULL, p=2, max.dist)

Arguments

x

Vector of x-coordinates of underlying points

y

Vector of y-coordinates of underlying points

districts

Either NULL or a vector of names for labeling points. If districts=NULL, points are labelled by index.

p

Any p-norm with p>=1 can be chosen as the distance measure with the Euclidian distance (p=2) being the default. For p=Inf, the maximum of coordinates is used. Except for p=Inf, calculations can fail for huge p.

max.dist

Value which determines the neighborship. Points whose distance is smaller or equal than max.dist are considered as neighbors.

Value

List of two elements: map object in graph format and map object in boundary format.

Author(s)

Felix Heinzl, Thomas Kneib

See Also

read.gra,read.bnd,drawmap

Examples

x <- c(3,3,5,9.5,11,11)
y <- c(2,4,4,6,4.5,5)
xymap <- createxymap(x, y, districts=c("A","B","C","D","E","F"), max.dist=2)
xymap$gra
drawmap(map=xymap$bnd)