使用rworldmap添加点以表示世界地图上的城市

Question

我想做一个世界地图与特定的国家填写，但如果可能的话，我也想包括具体的城市代表国家的精确点。

我一直在使用rworldmap包，并与其他人进行了实验，但我很难理解如何定位特定的城市位置，以及如何将mapbubbles包含在其中。

也许我可以加上这样的一行，代表圣迭戈，但我不知道它会去哪里：

mapBubbles(dF="CEAMap", nameX = "-117.16", nameY = "32.71", nameZSize = "CEAMap",)

我一直在阅读开发人员的PDF文档，老实说，我不能真正理解如何实现地图泡泡，以及像nameZsize这样的东西最初应该包含哪些内容。

我用这个指南来学习如何突出这些国家，但就精确定位城市而言，我似乎只能靠自己，因为我无法真正理解开发人员的PDF。How to create a world map in R with specific countries filled in?

到目前为止，这是我的完整代码：

library(rworldmap)
library(ggmap)
library(maptools)
library(maps)

theCountries <- c("USA", 
                  "CAN", "DEU", "FRA", "IND", 
                  "GBR", "NLD", "ITA", 
                  "CHN", "KOR", "JPN", 
                  "ESP", "PRT", "RUS", 
                  "NOR", "SGP", "AUS", 
                  "CHL", "MEX", "PHL", "RWA", 
                  "JOR", "HND", "PAN", "THA", "DOM", 
                  "ZAF", "TUR", "CHE", "FIN",
                  "SEN", "BOL", "OMN", "PAK", "CMR", "MUS", "BEL", "MYS", 
                  "UAE", "BRA", "MLI", "MOZ", "NAM", "EGY", "ARG", "UKR", "ZMB", "KEN",
                  "VNM", "NGA", "DNK", "IRN", "AFG")
# These are the ISO3 names of the countries you'd like to plot in red

CEAMap <- data.frame(country = c("USA", 
                                 "CAN", "DEU", "FRA", "IND", 
                                 "GBR", "NLD", "ITA", 
                                 "CHN", "KOR", "JPN", 
                                 "ESP", "PRT", "RUS", 
                                 "NOR", "SGP", "AUS", 
                                 "CHL", "MEX", "PHL", "RWA", 
                                 "JOR", "HND", "PAN", "THA", "DOM", 
                                 "ZAF", "TUR", "CHE", "FIN",
                                 "SEN", "BOL", "OMN", "PAK", "CMR", "MUS", "BEL", "MYS", 
                                 "UAE", "BRA", "MLI", "MOZ", "NAM", "EGY", "ARG", "UKR", "ZMB", "KEN",
                                 "VNM", "NGA", "DNK", "IRN", "AFG"),
                      involvement = c(1, 
                                    2, 2, 2, 2, 
                                    3, 3, 3, 
                                    4, 4, 4, 
                                    5, 5, 5, 
                                    6, 6, 6, 
                                    7, 7, 7, 7,
                                    8, 8, 8, 8, 8,
                                    9, 9, 9, 9,
                                    10, 10, 10, 10, 10, 10, 10, 10, 
                                    11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 
                                    12, 12, 12, 12, 12))

# CEAMap is a data.frame with the ISO3 country names plus a variable to
# merge to the map data

CEAcountries <- joinCountryData2Map(CEAMap, joinCode = "ISO3",
                              nameJoinColumn = "country")


# This will join your CEAMap data.frame to the country map data

mapCountryData(CEAcountries, nameColumnToPlot="country", 
               catMethod = "categorical",
               mapTitle='CEA Locations',
               missingCountryCol = gray(.8))

我希望有一些具体的要点，突出城市的填充在国家。

Answer 1

我希望有一些具体的要点，突出城市的填充在国家。

那么mapBubbles()是错误的函数。您可以像普通的R-图中那样添加points()。

获取城市之前的位置数据：

library(maps)

data("world.cities")

plotcities <- subset(world.cities, capital == 1)

我不知道你对哪些城市感兴趣，所以我只选择了首都

mapCountryData(CEAcountries, nameColumnToPlot="country", 
               catMethod = "categorical",
               mapTitle='CEA Locations',
               missingCountryCol = gray(.8), addLegend = FALSE)
points(plotcities$long, plotcities$lat, pch =  18, col = "black")

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不过，我建议您看看像tmap这样的包。他们制作的地图要好得多。ggplot2也可能是一个更好的选择。

编辑：使用您提供的城市，只需相应地选择：

plotcities <- subset(world.cities, 
                     name %in% c("Cologne", "Chennai", "Denver", "Madrid", "Manila", "San Diego", "Seattle", "Shanghai")
                     & country.etc %in% c("Germany", "USA", "Spain", "China", "Philippines", "India"))