如何制作没有南极洲的世界地图？

Question

我正在使用rworldmap包制作世界地图。我正在使用一个函数来访问UN Comtrade的交易数据。

我编辑了我原来的问题所以我可以展示一个我正在做的事情的真实例子。这是我可以制作的地图：

功能

library(rjson)
library(rworldmap)

get.Comtrade <- function(url="http://comtrade.un.org/api/get?", maxrec=50000,
                         type="C", freq="A", px="HS", ps="now", r, p, rg="all",
                         cc="TOTAL", fmt="json") {
  string <- paste(url
                  , "max=", maxrec,"&"  # maximum no. of records returned
                  , "type=", type, "&"  # type of trade (c=commodities)
                  , "freq=", freq, "&"  # frequency
                  , "px=", px, "&"      # classification
                  , "ps=", ps, "&"      # time period
                  , "r=", r, "&"        # reporting area
                  , "p=", p, "&"        # partner country
                  , "rg=", rg, "&"      # trade flow
                  , "cc=", cc, "&"      # classification code
                  , "fmt=", fmt         # Format
                  , sep="")

  if (fmt == "csv") {
    raw.data <- read.csv(string,header=TRUE)
    return(list(validation=NULL, data=raw.data))
  } else {
    if (fmt == "json" ) {
      raw.data <- fromJSON(file=string)
      data <- raw.data$dataset
      validation <- unlist(raw.data$validation, recursive=TRUE)
      ndata <- NULL
      if (length(data) > 0) {
        var.names <- names(data[[1]])
        data <- as.data.frame(t(sapply(data,rbind)))
        ndata <- NULL
        for (i in 1:ncol(data)) {
          data[sapply(data[, i], is.null), i] <- NA
          ndata <- cbind(ndata, unlist(data[, i]))
        }
        ndata <- as.data.frame(ndata)
        colnames(ndata) <- var.names
      }
      return(list(validation=validation, data=ndata))
    }
  }
}

用法

dt2 <- get.Comtrade(r=32, p="all", rg=1, fmt="csv")
dt2df <- as.data.frame(do.call(rbind, dt2))
total <- sum(dt2df$Trade.Value..US..)
dt2df$p <- 100*dt2df$Trade.Value..US../total
dt2df <- dt2df[order(-dt2df[, "p"]), ]

top3 <- dt2df[4, "p"]
top10 <- dt2df[11, "p"]
q3 <- dt2df[as.integer(1*nrow(dt2df)/4), "p"]
q2 <- dt2df[as.integer(2*nrow(dt2df)/4), "p"]
q1 <- dt2df[as.integer(3*nrow(dt2df)/4), "p"]

mapped_data <- joinCountryData2Map(dt2df, joinCode="ISO3", 
                                   nameJoinColumn="Partner.ISO")

mapCountryData(mapped_data, nameColumnToPlot="p", numCats=6, 
               catMethod=c(0, q1, q2, q3, top10, top3, 100), 
               colourPalette=c('cornsilk', 'cornsilk2', 'palegreen1', 
                               'palegreen2', 'palegreen4', 'darkgreen'), 
               mapTitle="", addLegend=FALSE)

结果是我正在寻找的地图，除了我不需要看到南极洲。我该如何删除它？

我尝试使用xlim和ylim，但它没有用。

Answer 1

试试new_world <- subset(mapped_data, continent != "Antarctica")

后

mapped_data <- joinCountryData2Map(dt2df, joinCode = "ISO3", nameJoinColumn = "Partner.ISO")

然后继续

mapCountryData(new_world, nameColumnToPlot = "p", numCats=6, catMethod = 
c(0,q1,q2,q3,top10,top3,100), colourPalette =     c('cornsilk','cornsilk2','palegreen1','palegreen2','palegreen4','darkgreen'), mapTitle="", addLegend=FALSE)