如何使用 R 基于某些数据绘制纽约市社区的热图？ [关闭]

Question

对于我目前正在做的一个项目，我必须使用 R 根据某些输入绘制纽约市社区的热图。我搜索了这个主题，发现在 R 中有一个名为“map”的包将允许您很容易地绘制美国各州的热图。但是，我不知道如何为一个城市绘制类似的热图，特别是纽约市？任何建议都非常感谢。

Answer 1

关于 SO 有很多答案可以帮助您用颜色填充 shapefile 多边形。我同意@42- 你没有表现出任何工作/努力，但这可能有助于其他人希望对纽约社区区数据做类似的事情。所以，为了更大的利益：

library(rgeos)
library(maptools)
library(geojsonio)
library(ggplot2)

# this is the geojson of the NYC community districts
URL <- "http://services5.arcgis.com/GfwWNkhOj9bNBqoJ/arcgis/rest/services/nycd/FeatureServer/0/query?where=1=1&outFields=*&outSR=4326&f=geojson"
fil <- "nyc_community_districts.geojson"
if (!file.exists(fil)) download.file(URL, fil)

nyc_districts <- geojson_read(fil, what="sp")

# the @data slot of nyc_districts has 2 fields. BoroCD is the district #
nyc_districts_map <- fortify(nyc_districts, region="BoroCD")

# let's see which id is what
mids <- cbind.data.frame(as.data.frame(gCentroid(nyc_districts, byid=TRUE)), 
                         id=nyc_districts$BoroCD)

gg <- ggplot()
gg <- gg + geom_map(data=nyc_districts_map, map=nyc_districts_map,
                    aes(x=long, y=lat, map_id=id),
                    color="#2b2b2b", size=0.15, fill=NA)
gg <- gg + geom_text(data=mids, aes(x=x, y=y, label=id), size=2)
gg <- gg + coord_map()
gg <- gg + ggthemes::theme_map()
gg

# example choropleth

# we'll just make the map look like the Flash map on the NYC site
colorize <- function(x) {
  switch(substr(x, 1, 1),
         `1`="#86e3ff",
         `2`="#fffe9b",
         `3`="#ffc75f",
         `4`="#e7ceff",
         `5`="#dffd8b")
}

choro <- data.frame(district=nyc_districts@data$BoroCD,
                    fill=sapply(nyc_districts@data$BoroCD, colorize))

gg <- ggplot()
gg <- gg + geom_map(data=nyc_districts_map, map=nyc_districts_map,
                    aes(x=long, y=lat, map_id=id),
                    color="#2b2b2b", size=0.15, fill=NA)
gg <- gg + geom_map(data=choro, map=nyc_districts_map,
                    aes(fill=fill, map_id=district),
                    color="#2b2b2b", size=0.15)
# in a real choropleth you'd make colors map to values
# so i'm definitely leaving you some work to do vs just
# copy/paste for fun and profit
gg <- gg + scale_fill_identity()
gg <- gg + coord_map()
gg <- gg + ggthemes::theme_map()
gg

# better color palette
library(viridis)

# make up some fill data
set.seed(1492)
choro <- data.frame(district=nyc_districts@data$BoroCD,
                    fill=sample(100, nrow(nyc_districts@data)))

gg <- ggplot()
gg <- gg + geom_map(data=nyc_districts_map, map=nyc_districts_map,
                    aes(x=long, y=lat, map_id=id),
                    color="#2b2b2b", size=0.15, fill=NA)
gg <- gg + geom_map(data=choro, map=nyc_districts_map,
                    aes(fill=fill, map_id=district),
                    color="#2b2b2b", size=0.15)
gg <- gg + scale_fill_viridis(name="Better title\nthan 'fill'")
gg <- gg + coord_map()
gg <- gg + ggthemes::theme_map()
gg <- gg + theme(legend.position=c(0.1,0.5))
gg