4

ggplot2を使用して地図上にスケールバーと北向き矢印を描画するための任意のソリューション

library(mapdata); library(ggplot2); 
nl.map=data.frame(map('worldHires', 'Netherlands')[c('x', 'y')])
ggplot(nl.map, aes(x, y))+geom_path()

御時間ありがとうございます。

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2 に答える 2

5

数年前、私はスケールバーを描画できるコードを作成しました(r-sig-geoに関するこの投稿も参照してください)。これは、当時私が書いたコードです。あなたはそれを試してみることができます:

最初にいくつかのサポート機能:

makeNiceNumber = function(num, num.pretty = 1) {
   # Rounding provided by code from Maarten Plieger
   return((round(num/10^(round(log10(num))-1))*(10^(round(log10(num))-1))))
}

createBoxPolygon = function(llcorner, width, height) {
   relativeCoords = data.frame(c(0, 0, width, width, 0), c(0, height, height, 0, 0))
   names(relativeCoords) = names(llcorner)
   return(t(apply(relativeCoords, 1, function(x) llcorner + x)))
}

そして実際の機能:

addScaleBar = function(ggplot_obj, spatial_obj, attribute, addParams = 
list()) {
   addParamsDefaults = list(noBins = 5, xname = "x", yname = "y", unit = "m", 
        placement = "bottomright", sbLengthPct = 0.3, sbHeightvsWidth = 1/14)
   addParams = modifyList(addParamsDefaults, addParams)

   range_x = max(spatial_obj[[addParams[["xname"]]]]) - min(spatial_obj[[addParams[["xname"]]]])
   range_y = max(spatial_obj[[addParams[["yname"]]]]) -  min(spatial_obj[[addParams[["yname"]]]])
   lengthScalebar = addParams[["sbLengthPct"]] * range_x
   ## OPTION: use pretty() instead
   widthBin = makeNiceNumber(lengthScalebar / addParams[["noBins"]])
   heightBin = lengthScalebar * addParams[["sbHeightvsWidth"]]
   lowerLeftCornerScaleBar = c(x = max(spatial_obj[[addParams[["xname"]]]]) - (widthBin * addParams[["noBins"]]), y = min(spatial_obj[[addParams[["yname"]]]]))
   scaleBarPolygon = do.call("rbind", lapply(0:(addParams[["noBins"]] - 1), function(n) {
     dum = data.frame(createBoxPolygon(lowerLeftCornerScaleBar + c((n * widthBin), 0), widthBin, heightBin))
     if(!(n + 1) %% 2 == 0) dum$cat = "odd" else dum$cat = "even"
     return(dum)
   }))
   scaleBarPolygon[[attribute]] = min(spatial_obj[[attribute]])
   textScaleBar = data.frame(x = lowerLeftCornerScaleBar[[addParams[["xname"]]]] + (c(0:(addParams[["noBins"]])) * widthBin), y = lowerLeftCornerScaleBar[[addParams[["yname"]]]],
                             label = as.character(0:(addParams[["noBins"]]) * widthBin))
   textScaleBar[[attribute]] = min(spatial_obj[[attribute]])

   return(ggplot_obj +
     geom_polygon(data = subset(scaleBarPolygon, cat == "odd"), fill = "black", color = "black", legend = FALSE) +
     geom_polygon(data = subset(scaleBarPolygon, cat == "even"), fill = "white", color = "black", legend = FALSE) +
     geom_text(aes(label = label), color = "black", size = 6, data = textScaleBar, hjust = 0.5, vjust = 1.2, legend = FALSE))
}

そしていくつかのサンプルコード:

library(ggplot2)
library(sp)

data(meuse)
data(meuse.grid)
ggobj = ggplot(aes(x = x, y = y, color = zinc), data = meuse) + geom_point()
# Make sure to increase the graphic device a bit
addScaleBar(ggobj, meuse, "zinc", addParams = list(noBins = 5))
于 2013-03-18T21:08:04.793 に答える
2

ggsnというライブラリがあり、スケールバーと北向き矢印をカスタマイズできます。

ggplot() +
  geom_path(aes(long, lat, group=group), data=worldUk, color="black", fill=NA) +
  coord_equal() +
  ggsn::scalebar(worldUk, dist = 100, st.size=3, height=0.01, dd2km = TRUE, model = 'WGS84')

ここに画像の説明を入力してください

于 2018-06-06T02:15:33.940 に答える