Plotting Map in R (Track Values Falling out of a specific region)

Question

我已经在R中绘制了一个地图，该地图对应于我拥有的经纬度值，某些经纬度值落在特定区域之外（假设印度），有没有办法知道那些经纬度值呢？

Answer 1

Here's an example

library(sp)
spoly = SpatialPolygons(list(Polygons(list( Polygon(cbind(c(2,4,4,1,2),c(2,3,5,4,2))) ), "s1")), 1L)
spoints <- SpatialPoints(matrix(c(1:4, 2:5), ncol=2))
plot(spoly)
plot(spoints, add=T)
axis(1);axis(2)

(ov <- spoints %over% spoly)
#  1  2  3  4 
# NA  1  1  1 
coordinates(spoints)[is.na(ov),]
# coords.x1 coords.x2 
#         1         2 

See help("%over%") for all the variations.