centdist: Centroid Distance Between Two Identified Objects
Description
Find the centroid distance between two identified objects/features.
Usage
centdist(x, y, distfun = "rdist", loc = NULL, ...)
Value
numeric giving the centroid distance.
Arguments
x,y
objects of class “owin” (package spatstat) containing binary images of features of interest.
distfun
character string naming a distance function that should take arguments x1 and x2 as 1 by 2 matrices, and return a single numeric value. Default uses the fields function, rdist, where the fields function rdist.earth is an obvious alternative.
loc
two-column matrix giving the location values for which to calculate the centroids. If NULL, indices according to the dimension of the fields are used.
...
optional arguments to distfun.
Author
Eric Gilleland
Details
This is a simple function that calculates the centroid for each of x and y (to get their centroids), and then finds the distance between them according to distfun. The centroids are calculated using FeatureProps.
x <- y <- matrix(0, 10, 12)
x[2:3,c(3:6, 8:10)] <- 1y[c(4:7, 9:10),c(7:9, 11:12)] <- 1
x <- as.im(x)
x <- solutionset(x>0)
y <- as.im(y)
y <- solutionset(y>0)
centdist(x,y)