Question

我对使用R相对较新，我正在尝试使用数据来创建美国各州的地图，以便勾画并为某些区域着色。我试图以黑色显示一个州及其县。最重要的是，我想在各县之间创建厚红色边框，并根据我的一些数据填充一些县。

基本上我想组合这两个图像：

I would like to changed this map to outlines of the coloured areas, so -for example - there would be a red border around everything blue.

Then I would like to fill the map above like this

这是我到目前为止尝试此任务的代码：

# Maping IA, plan 74406IA0010001

# Importing data 
library(ggplot2) 
library(ggmap) 
library(maps) 
library(mapdata) 
library(stringr) 
library(plyr) 
library(dplyr)

setwd("/Users/erinmay/Desktop/WL_RA/marketplace2/data")

county <- map_data("county") 
plan <- read.csv("IA_2017.csv")

# Using subset

iowa <- subset(county, region=="iowa") #county point files for iowa

# Merging in map data

countyplan <- merge(x=iowa, y=plan, by=c("region","subregion"), all.x=TRUE)

countyplan <- countyplan[order(countyplan$chosen_plan),]

# Creating map  

final <- ggplot(data=countyplan) + 
           geom_path(aes(x=long,y=lat,group=RatingArea),colour='black') +  
           geom_polygon(aes(x=long,y=lat,group=group,fill=chosen_plan)) + 
           coord_map() + coord_fixed(1.3)

ggsave(final,height=6,width=10,unit='in',file='iowa.pdf')

先谢谢你的帮助！

以下是数据： https://www.dropbox.com/s/x8x2l50dvmg0lsb/QHP_IA_2017.csv?dl=0

Answer 1

根据OP的澄清编辑回答，仅为每个评级区域的外部边框着色：

据我了解，所有多边形在ggplot方面都是相同的。因此，如果必须为多边形的轮廓着色，则无论两个相邻多边形是否属于同一评级区域，它都将对所有边进行着色。

您将在相同的计划区域中使用溶解多边形，之前将它们强化为数据框。（注意：您可以将现有数据框转换回多边形，但可能更容易从原始数据源获取多边形数据。）

library(maps); library(dplyr); library(tidyr); library(maptools); library(rgeos) # get map data county_map <- map("county", fill = T, plot = FALSE) # create mapping table between county names & rating areas county_map_match <- data.frame(name = county_map$names) %>% separate(name, c("region", "subregion"), sep = ",", remove = FALSE) %>% left_join(plan %>% select(region, subregion, RatingArea)) rownames(county_map_match) <- county_map_match$name # convert map to SpatialPolygon, then join with mapping table for SpatialPolygonDataFrame county_map <- map2SpatialPolygons(county_map, IDs = county_map$names) county_map <- SpatialPolygonsDataFrame(county_map, county_map_match) # remove invalidities in the county map gIsValid(county_map) #returns FALSE: there are invalid self-intersecting geometries in the polygons, which will cause problems county_map <- gBuffer(county_map, byid = TRUE, width = 0) gIsValid(county_map) #returns TRUE # dissolve county map by rating area & fortify to data frame area_map <- unionSpatialPolygons(county_map, IDs = county_map$RatingArea) area_map <- fortify(area_map) area_map$group <- gsub(".1", "", x= area_map$group, fixed = T)

获得评级区域的数据框版本后，您可以将其合并到ggplot中：

ggplot(countyplan, aes(x=long,y=lat, group = group, fill = chosen_plan)) + geom_polygon(size = 0.5, colour = "black") + geom_polygon(data = area_map, aes(x=long, y=lat, group = group, colour = group), fill = NA, size = 2) + scale_fill_manual(name = "Chosen Plan", values = c("darksalmon"), na.value = "grey") + scale_color_discrete(name = "Rating Area") + coord_map() + coord_fixed(1.3)

您可以从RColorBrewer包中获得更好的调色板＆amp;如果您愿意，可以在scale_XX_brewer()电话中使用它们。可在此处引用各种颜色的名称：http://sape.inf.usi.ch/quick-reference/ggplot2/colour

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