R ggplot2/ggmap同心圆为点

Question

我想绘制一些信息，显示全部人口，然后在地图上显示该人口的子集。我已经看到使用同心圆或三维倒锥体传达这一点的数据可视化。我只是无法弄清楚如何做到这一点的ggplot/ggmap

下面是Paint放开手脚版本，显示的就是我希望做一个粗略的想法：

这里有一个粗略的一块的数据为例：

> dput(df1) 
structure(list(zip = c("00210", "00653", "00952", "02571", "04211", 
"05286", "06478", "07839", "10090", "11559"), city = c("Portsmouth", 
"Guanica", "Sabana Seca", "Wareham", "Auburn", "Craftsbury", 
"Oxford", "Greendell", "New York", "Lawrence"), state = c("NH", 
"PR", "PR", "MA", "ME", "VT", "CT", "NJ", "NY", "NY"), latitude = c(43.005895, 
17.992112, 18.429218, 41.751554, 44.197009, 44.627698, 41.428163, 
41.12831, 40.780751, 40.61579), longitude = c(-71.013202, -66.90097, 
-66.18014, -70.71059, -70.239485, -72.434398, -73.12729, -74.678956, 
-73.977182, -73.73126), timezone = c(-5L, -4L, -4L, -5L, -5L, 
-5L, -5L, -5L, -5L, -5L), dst = c(TRUE, FALSE, FALSE, TRUE, TRUE, 
TRUE, TRUE, TRUE, TRUE, TRUE), totalPop = c(43177, 37224, 37168, 
15492, 1614, 88802, 2587, 80043, 78580, 87461), subPop = c(42705, 
36926, 27556, 10827, 774, 39060, 1542, 21304, 53438, 2896)), .Names = c("zip", 
"city", "state", "latitude", "longitude", "timezone", "dst", 
"totalPop", "subPop"), row.names = c(1L, 50L, 200L, 900L, 1500L, 
2000L, 2500L, 3000L, 3500L, 4000L), class = "data.frame") 

有什么建议吗？

Answer 1

的基本思路是使用单独的geoms两个群体，确保较小的一个之后较大的一个绘制的，所以它的层之上：

library(ggplot2) # using version 0.9.2.1 
library(maps) 

# load us map data 
all_states <- map_data("state") 

# start a ggplot. it won't plot til we type p 
p <- ggplot() 

# add U.S. states outlines to ggplot 
p <- p + geom_polygon(data=all_states, aes(x=long, y=lat, group = group), 
    colour="grey", fill="white") 

# add total Population 
p <- p + geom_point(data=df1, aes(x=longitude, y=latitude, size = totalPop), 
    colour="#b5e521") 

# add sub Population as separate layer with smaller points at same long,lat 
p <- p + geom_point(data=df1, aes(x=longitude, y=latitude, size = subPop), 
    colour="#00a3e8") 

# change name of legend to generic word "Population" 
p <- p + guides(size=guide_legend(title="Population")) 

# display plot 
p 

从地图，很明显，您的数据包含非连续美国地区，在这种情况下，您可能需要不同的底层地图数据。 get_map()从ggmap包提供几个选项：

require(ggmap) 
require(mapproj) 
map <- get_map(location = 'united states', zoom = 3, maptype = "terrain", 
     source = "google") 
p <- ggmap(map) 

后其中添加的总和子种群geom_point（）层和用作前显示它。