在R中的空间点数据周围创建缓冲区，并计算缓冲区中有多少个点 [英] Create buffer around spatial point data in R and count how many points are in the buffer

问题描述

我正在尝试使用R分析加油站点的空间密度。我需要在加油站周围创建一个缓冲区（圆圈），并计算缓冲区内加油站的数量。然后，我需要四处寻找缓冲区的距离，看看有什么有趣的缓冲区是合理的。这些是我正在使用的文件： https://dl.dropboxusercontent.com/u /45095175/sbc_gas.shp ； https://dl.dropboxusercontent.com/u/45095175/sbc_gas.shx; https://dl.dropboxusercontent.com/u/45095175/sbc_gas.dbf

I am trying to analyze spatial density of gas station points using R. I need to create a buffer (circle) around the gas stations and count the number of gas stations within the buffer. I'll then need to play around with buffer distances to see what's a reasonable buffer to see something interesting. These are the files I am working with: https://dl.dropboxusercontent.com/u/45095175/sbc_gas.shp; https://dl.dropboxusercontent.com/u/45095175/sbc_gas.shx; https://dl.dropboxusercontent.com/u/45095175/sbc_gas.dbf

# Install packages 
x <- c("ggmap", "rgdal", "rgeos", "maptools", "ks")
lapply(x, library, character.only = TRUE)
all <- readShapePoints("sbc_gas.shp") 
all.df <- as(all, "data.frame")
locs <- subset(all.df, select = c("OBJECTID", "Latitude", "Longitude"))
head(locs)  # a simple data frame with coordinates
coordinates(locs) <- c("Longitude", "Latitude")  # set spatial  coordinates
plot(locs)

任何帮助都非常感谢！

推荐答案

我发现了我的问题的答案： 5公里<-cbind（坐标（位置），X = rowSums（distm（坐标（位置）[，1：2]，fun = distHaversine））/ 1000< = 5 ））＃5公里内的点数

I found an answer to my question: fivekm <- cbind(coordinates(locs), X=rowSums(distm (coordinates(locs)[,1:2], fun = distHaversine) / 1000 <= 5)) # number of points within 5 km

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