[英]Combine Voronoi polygons and maps
我想將Voronoi多邊形與地圖結合起來,以便稍后用於空間分析。 我有多個點和shapefile,我想要組合,然后保存為shapefile /空間多邊形。 要獲得voronoi多邊形,我使用本主題中的函數。
我的代碼如下:
coords<-data.frame(LONG=c(16.9252,16.9363,16.9408,16.8720,16.9167,16.9461,16.9093,16.9457,16.9171,16.8506,16.9471,16.8723,16.9444,16.9212,16.8809,16.9191,16.8968,16.8719,16.9669,16.8845),
LAT=c(52.4064,52.4266,52.3836,52.3959,52.4496,52.3924,52.4012,52.3924,52.3777,52.4368,52.4574,52.3945,52.4572,52.3962,52.3816,52.3809,52.3956,52.3761,52.4236,52.4539))
我的地圖位於: https : //docs.google.com/file/d/0B-ZJyVlQBsqlSURiN284dF9YNUk/edit
library(rgdal)
voronoipolygons <- function(x) {
require(deldir)
if (.hasSlot(x, 'coords')) {
crds <- x@coords
} else crds <- x
z <- deldir(crds[,1], crds[,2])
w <- tile.list(z)
polys <- vector(mode='list', length=length(w))
require(sp)
for (i in seq(along=polys)) {
pcrds <- cbind(w[[i]]$x, w[[i]]$y)
pcrds <- rbind(pcrds, pcrds[1,])
polys[[i]] <- Polygons(list(Polygon(pcrds)), ID=as.character(i))
}
SP <- SpatialPolygons(polys)
voronoi <- SpatialPolygonsDataFrame(SP, data=data.frame(x=crds[,1],
y=crds[,2], row.names=sapply(slot(SP, 'polygons'),
function(x) slot(x, 'ID'))))
}
我的代碼來獲取voronoipolygons:
pzn.coords<-voronoipolygons(coords)
plot(pznall)
plot(pzn.coords,add=T)
points(coords$LONG,coords$LAT)
結果:
我想把我的地圖中的這個voronoi多邊形作為新的空間多邊形。
對於冬天我會很感激!
編輯:
要清楚,我想實現這樣的東西(這些行應該從voronoi多邊形創建):
略微修改的函數,采用額外的空間多邊形參數並擴展到該框:
voronoipolygons <- function(x,poly) {
require(deldir)
if (.hasSlot(x, 'coords')) {
crds <- x@coords
} else crds <- x
bb = bbox(poly)
rw = as.numeric(t(bb))
z <- deldir(crds[,1], crds[,2],rw=rw)
w <- tile.list(z)
polys <- vector(mode='list', length=length(w))
require(sp)
for (i in seq(along=polys)) {
pcrds <- cbind(w[[i]]$x, w[[i]]$y)
pcrds <- rbind(pcrds, pcrds[1,])
polys[[i]] <- Polygons(list(Polygon(pcrds)), ID=as.character(i))
}
SP <- SpatialPolygons(polys)
voronoi <- SpatialPolygonsDataFrame(SP, data=data.frame(x=crds[,1],
y=crds[,2], row.names=sapply(slot(SP, 'polygons'),
function(x) slot(x, 'ID'))))
return(voronoi)
}
然后做:
pzn.coords<-voronoipolygons(coords,pznall)
library(rgeos)
gg = gIntersection(pznall,pzn.coords,byid=TRUE)
plot(gg)
請注意, gg
是一個SpatialPolygons對象,您可能會收到有關不匹配的proj4字符串的警告。 您可能需要將proj4字符串分配給一個或另一個對象。
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