Connect nearest neighbor point

Question

I have a list of xy coordinates for 30 data points (green dots in the pic) and I would like to connect them together.

How can I do it in R? At the moment, I computed the distance matrix between each point by dist() to obtain the closest neighbor for each point. However this result in 30 edge pairs... sometimes multiple edges connect to the same point which is not I want :( How can I solve this problem in R?

  cities_num=10
  cor.matrix=matrix(0,nrow=cities_num,ncol=2)
  for (r in 1:cities_num){
  cor.matrix[r,]=c(sample(1:500, 1),sample(1:500, 1))}
  par(mar=c(4,4,2,4))
  plot(cor.matrix,pch=4,xlab="X coordinate",ylab="Y coordinate")
  centroid.x=mean(cor.matrix[,1])
  centroid.y=mean(cor.matrix[,2])
  bead_num=cities_num+20
  t=seq(0,pi*2,length=bead_num) 
  coords=t(rbind( centroid.x+sin(t)*10, centroid.y+cos(t)*10))
  for (point in 1:bead_num){
    symbols(x=coords[,1][point],y=coords[,2][point],circles=0.5,
            inches = FALSE, add = TRUE)
  }

Answer 1

Not sure what a "symbol point" is and there seemed to be too many undefined objects in your code so I made my own set of "points". If just a regular point then use polygon :

 dat <- data.frame(s=sin(seq(pi,-pi,length=25)),
                    c=cos(seq(pi,-pi,length=25)) )
 png();
     plot(0,0, xlim=c(-1.5,1.5),ylim=c(-1.5,1.5) );
       with(dat, points(s,c));
       with(dat, polygon(s,c) ) 
 dev.off()