Форумы GIS-Lab.info

Код: Выделить всё

# generate rings
sink("foo")
n.ring = 10
max.rad=10
set.seed(123)
n.pnt = sample(3:20,n.ring)
rad=runif(n.ring,3,max.rad-1)
m=matrix(0,nrow=sum(n.pnt)+n.ring,ncol=2)
ncol=round(sqrt(n.ring))
pos=0
for(i in 1:n.ring) {
  x.shift = i %% ncol
  y.shift = i %/% ncol
  x0 = i*x.shift*max.rad
  y0 = i*y.shift*max.rad
  for(j in 0:n.pnt[i]) {
    pos=pos+1
    delta = (2*pi)/n.pnt[i]
    m[pos,]=c(round(x0+rad[i]*cos(delta*j)),round(y0+rad[i]*sin(delta*j)))
    cat(m[pos,1]," ",m[pos,2],"\n")
  }
}
sink()

# plot points
plot(m)

# find rings
p=read.table("foo",header=FALSE)
state="new"
ring.list=list()
for(i in 1:nrow(p)) {
  if(state == "new") {
    cur.ring=as.double(p[i,])
    state="old"
  } else {
    cur.pnt=as.double(p[i,])
    cur.ring=rbind(cur.ring,cur.pnt)
    if(cur.pnt[1] == cur.ring[1,1] && cur.pnt[2] == cur.ring[1,2]) {
      state="new"; ring.list=append(ring.list,list(cur.ring)) 
    }
  }
}

# plot rings
for(i in 1:length(ring.list)) {
  points(ring.list[[i]],col="red",type="l")
}