cluster.overplot {plotrix}R Documentation

Shift overlying points into clusters.

Description

cluster.overplot checks for overlying points in the x and y coordinates passed. Those points that are overlying are moved to form a small cluster of up to nine points. For large numbers of overlying points, see count.overplot or sizeplot.

Usage

 cluster.overplot(x,y,away=NULL,tol=NULL)

Arguments

x,y Numeric data vectors or the first two columns of a matrix or data frame. Typically the x/y coordinates of points to be plotted.
away How far to move overlying points in user units. Defaults to the width of a lower case "o" in the x direction and 5/8 of the height of a lower case "o" in the y direction.
tol The largest distance between points that will be considered to be overlying. Defaults to 1/2 of the width of a lower case "o" in the x direction and 1/2 of the height of a lower case "o" in the y direction.

Value

A list with two components. For unique x-y pairs the elements will be the same as in the original. For overlying points up to eight additional points will be generated that will create a cluster of points instead of one.

Author(s)

Jim Lemon

See Also

count.overplot,sizeplot

Examples

 xy.mat<-cbind(sample(1:10,200,TRUE),sample(1:10,200,TRUE))
 plot(cluster.overplot(xy.mat),main="Cluster overplot test")

[Package plotrix version 2.2-8 Index]