結合Voronoi多邊形和地圖

Question

我想結合Voronoi多邊形和地圖，以便稍後用於空間分析。我想要合併然後保存爲shapefile /空間多邊形的點數和shapefile數量。要獲得voronoi多邊形，我使用this topic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，請訪問：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')))) 
} 

而且我的代碼來獲得voronoipolygons：

pzn.coords<-voronoipolygons(coords) 
plot(pznall) 
plot(pzn.coords,add=T) 
points(coords$LONG,coords$LAT) 

結果：

我想把這個voronoi多邊形放在我的地圖裏面作爲新的spatialpolygon。

我會感激的！

編輯：

需要明確的是，我想要實現這樣的事情（這行應的Voronoi多邊形創建）：

Answer 1

稍加修改功能，需要一個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) 

} 

然後做：

pzn.coords<-voronoipolygons(coords,pznall) 
library(rgeos) 
gg = gIntersection(pznall,pzn.coords,byid=TRUE) 
plot(gg) 

注意gg是SpatialPolygons對象，你可能會得到一個關於不匹配的字符串proj4警告。您可能需要將proj4字符串分配給其中一個或另一個對象。