R：如何通過數據值對voronoi tesselation進行着色？

Question

我想

1. 從SpatialPointDataFrame確定R中創建的Voronoi鑲嵌
2. 獲得SpatialPolygonDataFrame OK
3. 通過值在我原來的SpatialPointDataFrame如何上色它???

據： 我創建和更新的Voronoi鑲嵌，如下： 這裏更新：https://gis.stackexchange.com/questions/190917/r-voronoi-tesselation-from-long-lat-data。

我知道我可以通過圖書館顏色它（「dismo」）：https://gis.stackexchange.com/questions/136542/r-function-for-thiessen-polygons

然而，使用上述沃羅諾伊功能，在我voronoipolygons我只有一個變量：「假的」。但是，我想通過變量「z」來給我的多邊形着色 - 這不包含在我的.voro多邊形中。

voronoipolygons = function(layer) { 
    require(deldir) 
    crds = layer@coords 
    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(dummy = seq(length(SP)), 
                 row.names=sapply(slot(SP, 'polygons'), 
                            function(x) slot(x, 'ID')))) 
} 

我的問題是：如何通過"z"變量上色我.voro多邊形，和/或如何直接將其包含在上述voronoipolygons()功能？我不能只是將"z"變量添加到.voro@data，因爲值的順序已更改。我的R技能還沒有那麼強大..非常感謝你！

虛擬數據：

x <- c(32.5, 32.1, 33.5, 32.2, 33.0) 
y <- c(-2.2, -3.3, -2.3, -2.9, -3.0) 
z <- c(1, 2, 5, 8, 4) 

# make df 
df<-as.data.frame(cbind(x,y,z)) 
coordinates(df)<- ~ x + y #make SPDF 

df.voro <- voronoipolygons(df) # calculated VORONOI 

require('dismo') 
spplot(df.voro, "dummy") # colorize Polygons 

# add z variable to newly created data 
df.voro@data$z<-df$z ## !!! can't use this, because this change order of values in df !!! 
spplot(df.voro, "z") 

Answer 1

我知道了！如何修改Voronoi函數

我需要先從我的data.frame中讀取my.variable：my.variable = layer@data[,1]，然後將其添加到我的SP對象中：y.data = my.variable。

voronoipolygons2 = function(layer) { 
    require(deldir) 
    crds = layer@coords 
    z = deldir(crds[,1], crds[,2]) 
    w = tile.list(z) 
    my.variable = layer@data[,1] ## HERE 
    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(dummy = seq(length(SP)), 
                 my.data = my.variable, # HERE add new column to my voronoi data 
                 row.names=sapply(slot(SP, 'polygons'), 
                      function(x) slot(x, 'ID')))) 
} 

通過修改維諾函數創建沃羅諾伊鑲嵌多邊形：

df.voro2 <- voronoipolygons2(df) 

檢查我voronoi2數據看起來像

> df.voro2@data 
    dummy my.data 
1  1  1 
2  2  2 
3  3  5 
4  4  8 
5  5  4 

以及它們是如何從voronoi1數據不同

> df.voro@data 
    dummy 
1  1 
2  2 
3  3 
4  4 
5  5 

顯示兩者在一張紙上

require(gridExtra) 
grid.arrange(spplot(df.voro, "dummy", xlab = "x", ylab = "y", main = "original"), 
      spplot(df.voro2, "my.data", xlab = "x", ylab = "y", main = "z value applied !;-)")) 

TRADAAA spplots）