Hi All,
    I try to empoly Monte Carlo to find out the distribution of my data. The code is following
library(sp)
library(rgdal)
library(raster)
x<-readOGR(".", "finance")   #get one spatial file
N.list<-list()
for(i in 1:1000){  
Sample.x<-sample(1:7059,600)  #the shp file includes 7059 points，and I want get 600 of them by random sample
Point.x<-x[Sample.x,]  # get 600 points
distance.x<-pointDistance(Point.x,lonlat=FALSE) #Calculate the distance between any two points 600 
y<-distance.x/1000  # the Unit is  meter, but I want it become kilometer
y<-round(y,0)  #
split.point=seq(min(y),max(y),by=1) 
result<-hist(y,breaks=split.point)     #get the frequency of each distance 
N.list[[i]]<-result$counts     #put the result into the list
}
if without loop, the code is right. But the loop construct is important. The error ls: 
Error in x@coords[i, , drop = FALSE] : subscript out of bounds 





                                                    Jiaming Li
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