r - Points within buffer with the same id

Question

I have a buffer layer and a point layer:

 buffer_gdf
     ID
0    1A
1    1B
2    1C

and

 point_gdf
      ID
0     1A
1     1A
2     1A
3     1A
4     1A
5     1B
6     1B
7     1B
8     1B
9     1B
10    1B
11    1B
12    1B
13    1B
14    1C    
15    1C
16    1C
17    1C    
18    1C
19    1C
20    1C    
21    1C
22    1C

Is there a way to count how many points with ID=1A are within buffer ID=1A, how many points ID=1B are within buffer ID=1B, how many points ID=1C are within buffer ID=1C, and so on... I have more than 20000 buffers and more than 300000 points.

I'm using pandas but I can also use R.

Sorry, I didn't mention that some points are outside the buffers. I just need those within the buffers

标签： rpandasbuffergeopandas

Answer 1

Here, is one way in R

sapply(buffer_gdf$ID, function(x) sum(point_gdf$ID == x))
1A 1B 1C 
 5  9  9 

Or with outer

rowSums(outer(buffer_gdf$ID, point_gdf$ID, `==`))
[1] 5 9 9

---

If this should not consider buffer_gdf, table would be enough

table(point_gdf$ID)

Or do a subset and then get the table

with(point_gdf, table(ID[ID %in% buffer_gdf$ID]))

data

buffer_gdf <- structure(list(ID = c("1A", "1B", "1C")), class = "data.frame", row.names = c("0", 
"1", "2"))

point_gdf <- structure(list(ID = c("1A", "1A", "1A", "1A", "1A", "1B", "1B", 
"1B", "1B", "1B", "1B", "1B", "1B", "1B", "1C", "1C", "1C", "1C", 
"1C", "1C", "1C", "1C", "1C")), class = "data.frame", row.names = c("0", 
"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", 
"13", "14", "15", "16", "17", "18", "19", "20", "21", "22"))