R中的Choropleth映射问题

Question

编辑：我已经意识到我的问题的根源。我只有我有数据的县的计数信息，这比我要绘制的区域中的县数少。

按理说问题出在这几行代码：

mapnames <- map("county",plot=FALSE)[4]$names
colorsmatched <- d$colorBuckets [na.omit(match(mapnames ,d$stcon))]

对于如何从地图库中生成与 NY、NJ、CT 和 PA 中的县数相匹配的适当长度的向量，是否有人建议？我想合并我拥有的计数数据，并为我没有信息的县包括零。

我正在尝试按照此处描述的教程进行操作：http://www.thisisthegreenroom.com/2009/choropleths-in-r/

下面的代码执行，但它要么没有正确匹配我的数据集和 maps_counties 数据，要么没有按照我期望的顺序绘制它。例如，大纽约地区的结果区域没有显示密度，而宾夕法尼亚州的随机县显示密度最高。

我的数据表的一般格式是：

county state count
fairfield connecticut 17
hartford connecticut 6
litchfield connecticut 3
new haven connecticut 12
...
...
westchester new york 70
yates new york 1
luzerne pennsylvania 1

请注意，此数据按州和县排序，包括 CT、NJ、NY 和 PA 的数据。

首先，我读入我的数据集：

library(maps)
library(RColorBrewer)
d <- read.table("gissum.txt", sep="\t", header=TRUE)

#Concatenate state and county info to match maps library
d$stcon <- paste(d$state, d$county, sep=",")

#Color bins
colors = brewer.pal(5, "PuBu")
d$colorBuckets <- as.factor(as.numeric(cut(d$count,c(0,10,20,30,40,50,300))))

这是我的匹配

mapnames <- map("county",plot=FALSE)[4]$names
colorsmatched <- d$colorBuckets [na.omit(match(mapnames ,d$stcon))]

绘图：

map("county"
  ,c("new york","new jersey", "connecticut", "pennsylvania")
  ,col = colors[d$colorBuckets[na.omit(match(mapnames ,d$stcon))]]
  ,fill = TRUE
  ,resolution = 0
  ,lty = 0
  ,lwd= 0.5
)
map("state"
  ,c("new york","new jersey", "connecticut", "pennsylvania")
  ,col = "black"
  ,fill=FALSE
  ,add=TRUE
  ,lty=1
  ,lwd=2
)

map("county"
   ,c("new york","new jersey", "connecticut", "pennsylvania")
   ,col = "black"
   ,fill=FALSE
   ,add=TRUE
  , lty=1
  , lwd=.5
)
title(main="Respondent Home ZIP Codes by County")

我确定我错过了一些基本的内容：地图函数绘制项目的顺序 - 但我似乎无法弄清楚。谢谢您的帮助。如果您需要更多信息，请告诉我。

Answer 1

通过将您的数据与来自选定州的地图的数据合并，可以解决您的问题。这是你要找的吗？

library(maps);
library(RColorBrewer);

# Create Dummy Data Frame to Play With

d = rbind(c('fairfield','connecticut',17),c('westchester','new york',70), c('luzerne','pennsylvania',1));
d = data.frame(d);
names(d) = c("county", "state", "count");
d$count = as.numeric(as.character(d$count));
d$stcon = paste(d$state, d$county, sep=",");

# Extract mapnames for States

mapnames2 = map("county",c("new york","new jersey", "connecticut", "pennsylvania"),plot=FALSE)[4]$names;
mapnames2 = data.frame(mapnames2);
names(mapnames2) = "stcon";

# Merge with d

d = merge(mapnames2, d, all = T);
d$count[is.na(d$count)] = 0;


# Color bins
colors = brewer.pal(5, "PuBu");
d$colorBuckets = as.factor(as.numeric(cut(d$count,c(0,10,20,30,40,50,300))));

map("county"
  ,c("new york","new jersey", "connecticut", "pennsylvania")
  ,col = colors[d$colorBuckets]
  ,fill = TRUE
  ,resolution = 0
  ,lty = 0
  ,lwd= 0.5
)
map("state"
  ,c("new york","new jersey", "connecticut", "pennsylvania")
  ,col = "black"
  ,fill=FALSE
  ,add=TRUE
  ,lty=1
  ,lwd=2
)

map("county"
   ,c("new york","new jersey", "connecticut", "pennsylvania")
   ,col = "black"
   ,fill=FALSE
   ,add=TRUE
  , lty=1
  , lwd=.5
)
title(main="Respondent Home ZIP Codes by County")