有没有办法在“spatstat”包中使圆盘图的多边形边界不可见？

Question

Here is the plot. I want to get rid of the black line of the aperture.

I believe the pictures are pretty self explanatory for understanding what i would like to do. But i really have no idea how to go about this. Any help would be greatly appreciated.

But, i want it to look like the following:

Here is my code:

library(spatstat.data)
library(nlme)
library(rpart)
library(spatstat)

repelled_points <- function(n, r_circle, r_clash) {
        container_x <- numeric(n)
        container_y <- numeric(n)
        j <- i <- 1
        while(i <= n)
        {
                j <- j + 1
                if(j == 100 * n) stop("Cannot accommodate the points in given space")
                x <- runif(1, -1, 1)
                y <- runif(1, -1, 1)
                if(x^2 + y^2 > 1) next
                if(i > 1) {
                        dist <- sqrt((x - container_x[seq(i-1)])^2 + (y - container_y[seq(i-1)])^2)
                        if(any(dist < r_clash)) next
                }
                container_x[i] <- x
                container_y[i] <- y
                i <- i + 1
                j <- 1
        }
        `class<-`(list(window = disc(centre = c(0, 0), radius = r_circle),
                       n = n, x = container_x * r_circle,
                       y = container_y * r_circle, markformat = "none"), "ppp")
}
dots <- repelled_points(18, 1, 0.35)
plot(dots, type="n")
points(dots$x[1:4], dots$y[1:4], pch=15, col="chartreuse3", cex=6)
points(dots$x[5:8], dots$y[5:8], pch=15, col="chartreuse3", cex=6)
points(dots$x[9:13], dots$y[9:13], pch=17, col="chartreuse", cex=6)
points(dots$x[14:18], dots$y[14:18], pch=17, col="chartreuse", cex=6)

Thank you!

Answer 1

You can plot with lty = 0

plot(dots, type="n", lty = 0)
points(dots$x[1:4], dots$y[1:4], pch=15, col="chartreuse3", cex=6)
points(dots$x[5:8], dots$y[5:8], pch=15, col="chartreuse3", cex=6)
points(dots$x[9:13], dots$y[9:13], pch=17, col="chartreuse", cex=6)
points(dots$x[14:18], dots$y[14:18], pch=17, col="chartreuse", cex=6)

Answer 2

Your function repelled_points creates a point pattern (object of class "ppp" in the spatstat package). To learn how to plot it, read the help for plot.ppp . To select subsets, read the help for [.ppp .

dots <- repelled_points(18, 1, 0.35)
plot(Window(dots), type="n", main="")
plot(dots[1:4], pch=16, cols="chartreuse3", cex=6, add=TRUE)

Line 2 uses plot.owin and line 3 uses plot.ppp .

In this code I have assumed that you specifically wanted the first 4 points in the pattern to be plotted with the specified parameters.

More commonly, people want to use different graphical symbols to represent points with different "attributes". Perhaps the points are classified into several different types, and points of type 1 should always be plotted with a square, type 2 with a triangle, etc. In spatstat the attributes of the points would be encoded as "marks" of the point pattern. Then you could replace the three code lines above by a single line which calls plot.ppp with the required graphical information that maps the marks to symbols. See the examples in the help for plot.ppp .

See chapter 4 in the spatstat book for detailed information.