Edit Question - KnowledgeHub

Title Body

Package sp provides a number of classes for different spatial concepts (points, lines, polygons). For some classes, accessing feature coordinates is straightforward, e.g. SpatialLines . All examples were taken from respective class help pages. l1 = cbind(c(1,2,3),c(3,2,2)) l1a = cbind(l1[,1]+.05,l1[,2]+.05) l2 = cbind(c(1,2,3),c(1,1.5,1)) Sl1 = Line(l1) Sl1a = Line(l1a) Sl2 = Line(l2) S1 = Lines(list(Sl1, Sl1a), ID="a") S2 = Lines(list(Sl2), ID="b") Sl = SpatialLines(list(S1,S2)) coordinates(Sl) # [prints a list of two with corresponding segments] For SpatialPolygons , coordinates() returns polygon centers as demonstrated below. Sr1 = Polygon(cbind(c(2,4,4,1,2),c(2,3,5,4,2))) Sr2 = Polygon(cbind(c(5,4,2,5),c(2,3,2,2))) Sr3 = Polygon(cbind(c(4,4,5,10,4),c(5,3,2,5,5))) Sr4 = Polygon(cbind(c(5,6,6,5,5),c(4,4,3,3,4)), hole = TRUE) Srs1 = Polygons(list(Sr1), "s1") Srs2 = Polygons(list(Sr2), "s2") Srs3 = Polygons(list(Sr3, Sr4), "s3/4") SpP = SpatialPolygons(list(Srs1,Srs2,Srs3), 1:3) coordinates(SpP) [,1] [,2] [1,] 2.696970 3.545455 [2,] 3.666667 2.333333 [3,] 6.133333 3.933333 Is there a handy function in common packages that would extract feature coordinates? I have come up with a function for SpatialPolygons , but I'm looking for something that has been better tested and is consistent, perhaps even across most/all sp classes. getEdges <- function(x) { stopifnot(class(x) == "SpatialPolygons") lapply(x@polygons, function(y) { y@Polygons[[1]]@coords }) } getEdges(SpP) # [returns a list of three, coordinates in a matrix]

Tags (comma-separated) Cancel