R Buffer – Spatially Join/Merge Two Spatial Points Data Frames via Buffer

bufferpoint-in-polygonr

I'm trying to spatial join/merge two spatial points data frames in R. One data frame is lacking IDs, which is the information that needs to be joined to the other data frame. To be specific, any point from data frame 1 that falls within a 1500 m buffer of a point in data frame 2 should be joined with the respective ID from data frame 2. Here's some code to illustrate my problem:

library(mapview)
library(sp)
library(rgdal)
library(rgeos)

lat1 <- c(4417391,4517826, 4435680,4509372,4449390)
long1 <- c(5557780,5358439,5328731,5323168,5519670) 
attrib1 <- seq(6,10,1)
attrib2 <- seq(11,15,1)
df1 <- data.frame(lat1,long1,attrib1,attrib2)

lat2 <- c(4394822,4488830,4417257,4517995,4435679)
long2 <- c(5293795,5418630,5557927,5358272,5328084)
ID <- seq(1,5,1)
df2 <- data.frame(lat2,long2,ID)

coordinates(df1) <- ~lat1+long1
proj4string(df1) <- CRS("+init=EPSG:31468")

coordinates(df2) <- ~lat2+long2
proj4string(df2) <- CRS("+init=EPSG:31468")

buff <- gBuffer(df2,width=1500)
df1_buff <- df1[buff,]

mapview(buff) + mapview(df1,color="red") + mapview(df1_buff,color="green")

I have now selected the points from df1 that lie within the buffers of df2. However, the buffer obviously does not contain IDs and I'm at a loss about how to merge this infromation. I have looked into over and point.in.poly, but with no success. This is the result I'm looking for:

attrib1 attrib2 lat1     long1    ID
6       11      4417391  5557780  1
7       12      4517826  5358439  2
8       13      4435680  5328731  3

Best Answer

Is this what you are looking for? I just:

  • added one line of code right after proj4string(df1) <- CRS("+init=EPSG:31468")
  • added three lines of code at the end

And this is the code:

library(mapview)
library(sp)
library(rgdal)
library(rgeos)

lat1 <- c(4417391,4517826, 4435680,4509372,4449390)
long1 <- c(5557780,5358439,5328731,5323168,5519670) 
attrib1 <- seq(6,10,1)
attrib2 <- seq(11,15,1)
df1 <- data.frame(lat1,long1,attrib1,attrib2)

lat2 <- c(4394822,4488830,4417257,4517995,4435679)
long2 <- c(5293795,5418630,5557927,5358272,5328084)
ID <- seq(1,5,1)
df2 <- data.frame(lat2,long2,ID)

coordinates(df1) <- ~lat1+long1
proj4string(df1) <- CRS("+init=EPSG:31468")
df1@data<-cbind(df1@data,lat1,long1)

coordinates(df2) <- ~lat2+long2
proj4string(df2) <- CRS("+init=EPSG:31468")

buff <- gBuffer(df2,width=1500,byid=TRUE)
df1_buff <- df1[buff,]

mapview(buff) + mapview(df1,color="red") + mapview(df1_buff,color="green")


library(raster)
o<-over(df1_buff,buff)
df1_buff@data<-cbind(df1_buff@data,o)
df1_buff@data
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