sphet (version 1.0-0)

distance: Writes distance matrices

Description

Reads points coordinates and generates objects of class distance.matrix

Usage

distance(coord,region.id=NULL,output=TRUE,
type=c("NN","distance","inverse"),
measure=c("euclidean","gcircle","chebyshev","braycur","canberra"),
nn=6, cutoff=FALSE, miles=TRUE,R=NULL, shape.name=NULL,region.id.name=NULL,
firstline=FALSE,file.name=NULL)

Value

A matrix of three columns: from, to, and distance

Details

The object created is similar to the content of a 'GWT' file. The output file can be of any format. In particular, it could be a 'GWT' file. When firstline is TRUE, an header line is added to the 'GWT' file. The first element is simply a place holder, the second is the number of observations. The name of the shape file and of the id variable can be specified by the options shape.name and region.id.name respectively. The function performs a series of test on the region.id variable. If a region.id variable is not specified and coord only has two columns, a sequence from 1 to the number of observations is generated and used as identification variable. If region.id is specified and the first column of coord contains an id variable they should be the same.

Examples

X<-runif(100,0,70)
Y<-runif(100,-30,20)
coord1<-cbind(seq(1,100),X,Y)
thm1 <- distance(coord1,region.id=NULL,output=TRUE,type="inverse", shape.name="shapefile",region.id.name="id1",firstline=TRUE,file.name="dist_100.GWT")
thm2 <- distance(coord1,region.id=NULL,output=FALSE,type="NN", nn=6)
thm2 <- distance(coord1,region.id=NULL,output=FALSE,type="distance", cutoff=1)