小平面环绕扭曲了R中的状态图 [英] facet wrap distorts state maps in R

问题描述

此问题是我之前提出的问题的扩展，请参见使用小平面换行在R中映射不同的状态.我想在地图上显示点，并按其值着色.我可以使用下面的代码来完成此工作，该代码可以生成一个看起来不错的图，但我喜欢Mark Peterson提供的更好的'sepStates'输出外观.

This question is an extension of a previous question I asked, see Mapping different states in R using facet wrap. I want to display points in the maps, colored by their value. I can get this to work using the following code, which produces a decent looking plot, but I like the look of the 'sepStates' output that Mark Peterson provided better.

mn <- min(test$value); hist(test$value) 
mx <- max(test$value)
ggplot(map_data('state',region=states), aes(x=long,y=lat,group=group)) +
geom_polygon(colour='black',fill='white') + geom_point(data=test,aes
(x=Lon,   y=Lat, group=group, color=value),size=2.5, pch=16) +
facet_wrap(~region, scales = "free", ncol=3) + 
scale_colour_gradientn(limits = c(mn,mx),breaks=c
(2,3,4,5,6,7,8,9),colours=rev(rainbow(7)))

假设在提供的邮政编码数据Mark中添加了一个温度列.

Let's say there's a temperature column added to the zip code data Mark provided.

datatest <- structure(list(zip =c 
("5246", "85118", "85340", "34958", "33022", 
"32716", "49815", "48069", "48551", "58076", "58213", "58524", 
"73185", "74073", "73148", "98668", "98271", "98290"), 
city = c("Chandler","Gold Canyon", "Litchfield
Park", "JensenBeach", "Hollywood", "Altamonte
Springs", "Channing", "Pleasant Ridge", "Flint", "Wahpeton", 
"Ardoch", "Braddock", "Oklahoma City", "Sperry", "Oklahoma City", 
"Vancouver", "Marysville", "Snohomish"), state = c
("AZ", "AZ","AZ", "FL", "FL", "FL", "MI", "MI", "MI", "ND", "ND", "ND",
"OK","OK", "OK", "WA", "WA", "WA"), latitude = c(33.276539, 33.34,33.50835, 
27.242402, 26.013368, 28.744752, 46.186913, 42.472235, 
42.978995, 46.271839, 48.204374, 46.596608, 35.551409, 36.306323, 
35.551409, 45.801586, 48.093129, 47.930902), longitude = c(-112.18717,    
-111.42, -112.40523, -80.224613, -80.144217, -81.22328, -88.04546, 
-83.14051, -83.713124, -96.608142, -97.30774, -100.09497, -97.407537, 
-96.02081, -97.407537, -122.520347, -122.21614, -122.03976),
temperature = c(45,87,33,66,12,69,45,78,23,39,41,104,50,53,40,88,56,29)), 
.Names = c("zip", "city", "state", "latitude", "longitude","temperature"), 
row.names = c(NA, -18L), class = c("tbl_df", "tbl", "data.frame"))

如果我想按状态在各个方面(仅上面的1个图例)显示此内容，就像上面的第一个代码产生的那样，我该怎么做?我当前的代码如下:

If I want to display this in facets by state with only 1 legend on the right, like the first code above produces, how do I do this? My current code looks like this:

sepStates <- lapply(states, function(thisState){
ggplot(map_data('state',region=thisState), aes(x=long,y=lat,group=group)) +
geom_polygon(colour='black',fill='white') + geom_point(data=datatest
[datatest$region == tolower(thisState),],aes(x=long, y=lat, group=group,
color=temperature),size=2.5, pch=16) + ggtitle(thisState) + coord_map() +
theme_void() + theme(plot.title = element_text(hjust = 0.5))})

plot_grid(plotlist = sepStates)

使用'cowplot'软件包仍然会导致状态使用以下代码失真.任何帮助将不胜感激.

Using the 'cowplot' package still leads to the states being distorted using the following code. Any help would be greatly appreciated.

legend <- get_legend(ok_plot)
prow <- plot_grid(ok_plot + theme(legend.position="none"),
az_plot + theme(legend.position="none"),
mi_plot + theme(legend.position="right"),
nd_plot + theme(legend.position="none"),
fl_plot + theme(legend.position="none"),
wa_plot + theme(legend.position="right"),
align = 'vh',
hjust = -1,
nrow = 2)

谢谢！

推荐答案

您的方法看起来是正确的，但是您似乎忘记了包括一些关键组件(例如，数据和创建位置)对象ok_plot等.

Your approach looks like it is on the right track, but you appear to have forgotten to include a few key components (e.g., the data and where you created the objects ok_plot etc.).

首先，我发现最简单的方法是创建一个对象以容纳要使用的任何色阶.我不确定您要使用rainbow面板的位置，因为中断似乎与数据范围不匹配.因此，相反，我将使用viridis制作一个(调色板非常适合顺序数据).

First, I find it easiest to create an object to hold whatever color scale you want to use. I am not sure where you are going with the rainbow palette, as the breaks don't seem to match the extent of your data. So, instead, I am going to use viridis to make one (the palette is great for sequential data).

library(viridis)
sharedScale <-
  scale_color_viridis(limits = range(datatest$temperature))

然后，像以前一样创建单独的图.请注意，除了sharedScale之外，还添加了颜色映射，并且我立即取消了图例.

Then, create your separate plots as before. Note that there is a color mapping added, along with the sharedScale, and that I am suppressing the legends right away.

sepStates <-
  lapply(states, function(thisState){
    ggplot(map_data('state',region=thisState)
           , aes(x=long,y=lat,group=group)) +
      geom_polygon(colour='black',fill='white') +
      geom_point(aes(color = temperature)
                 , data = datatest[datatest$region == tolower(thisState), ]
                 , size = 4
                 , show.legend = FALSE) +
      sharedScale +
      ggtitle(thisState) +
      coord_map() +
      theme_void() +
      theme(plot.title = element_text(hjust = 0.5))
  })

像以前一样对此进行绘图，将提供您想要的地图(现在带有颜色).但是，它不会有图例.为此，我们希望提取一个图例以在所有地块中共享.在执行此操作时，请确保每个绘图中的值都相同(例如，您设置了限制).

plotting this, as before, will give the maps you want (now with color). However, it won't have a legend. For that, we want to extract a single legend to share across all of the plots. Make sure that the values are the same in every plot (e.g., that you set the limits) when you do this.

sharedLegend <-
  get_legend(
    ggplot(datatest
           , aes(x=long,y=lat,color = temperature)) +
      geom_point() +
      sharedScale +
      theme_void()
  )

现在，我们可以使用嵌套的plot_grid将它们缝合在一起.在内部，我们生成与以前相同的布局(仅六个状态).在外部，我们将其与图例结合在一起.您必须修改rel_widths才能匹配最终产品中所需的宽高比(和标题).

Now, we can stitch it all together using nested plot_grid. Inside, we generate the same layout as before (just the six states). Outside, we combine that with the legend. You will have to tinker with rel_widths to match the aspect ratio (and titling) that you want in your final product.

plot_grid(
  plot_grid(plotlist = sepStates)
  , sharedLegend
  , nrow = 1
  , rel_widths = c(6, 1)
)

给予

类似地，您可能要使用图例标题/大小(或考虑将其放在地图下方而不是旁边).

Similarly, you may want to play with the legend title/size (or consider putting it under the map instead of next to it).

flatLegend <-
  get_legend(
    ggplot(datatest
           , aes(x=long,y=lat,color = temperature)) +
      geom_point() +
      sharedScale +
      labs(color = "Temp") +
      theme_void() +
      theme(
        legend.title = element_text(size = 18, face = "bold")
        , legend.text = element_text(size = 12)
        , legend.key.size = unit(24, "points")
        , legend.position = "bottom")
  )

plot_grid(
  plot_grid(plotlist = sepStates)
  , flatLegend
  , ncol = 1
  , rel_heights = c(6, 1)
)

送礼

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