柵格單元格中shapefile的點數

Question

是否可以通過某種方式從Rsterfile的每個單元格中的shapefile中使用R來計算點的數量？

想法是檢索一個數據幀，該數據幀包含柵格中每個單元格的一行和該單元格中具有點數的列，同時保留柵格單元格的原始值。

Answer 1

這個答案在標題

library(rgdal)   # this package to read and manipulate shapefiles 
library(raster)   # this package for rasters 
shp <- readOGR("my_shape_file.shp")  # read in your points from the shape file 
ras <- raster("my_raster_file")   # read in your raster 
shp <- spTransform(shp, projection(ras)) # make sure that the two spatial objects share the same coordinate system 
cells <- cellFromXY(ras,shp)  # find which cells the points are in 
table(cells)      # and make a table of number of occurences in each cell 

Answer 2

library(raster) 
# example raster and points data 
r <- raster(ncols=10, nrows=5) 
n <- 100 
x <- runif(n) * 360 - 180 
y <- runif(n) * 180 - 90 
xy <- cbind(x, y) 

rp <- rasterize(xy, r, fun=function(x,...)length(x)) 
as.data.frame(rp)