R中的加拿大人口普查部门：无法开放

Question

我正在尝试关注第一个答案的第一部分here，复制并粘贴在下面：

library(rgeos)
library(rgdal)
library(maptools)
library(sp)
library(ggplot2)

# decent, uncluttered map theme (needs devtools package tho)
devtools::source_gist("https://gist.github.com/hrbrmstr/33baa3a79c5cfef0f6df")

# grab the file from "Statistics Canada"
download.file("http://www12.statcan.gc.ca/census-recensement/2011/geo/bound-limit/files-fichiers/gcd_000b11a_e.zip",
              destfile="gcd_000b11a_e.zip")

unzip("gcd_000b11a_e.zip")

# this simplifies the polygons so they load/plot faster
system("ogr2ogr canada.shp gcd_000b11a_e.shp -simplify 0.01")

# what layers do we have? you can use this to check
#   ogrListLayers("gcd_000b11a_e/canada.shp")
# but there are none, so the shapefile is the layer

canada <- readOGR("gcd_000b11a_e/","canada")

# do this to see what's available from an "identifier" standpoint
# "CDNAME" seems to be the census district name
# "PRNAME" seems to be the province name
# str(canada@data)

# rig up  some data
# make a data frame of census division areas
# you can assign as many value columns as you like
# they get merged in later and can be used as the fill level
# we'll use the area as the fill level
map_areas <- data.frame(id=canada@data$CDNAME,
                        area=sapply(slot(canada, "polygons"), slot, "area") )

# this takes a while, but it makes a data frame for use with
# ggplot and lets us use the census division name for doing things
# like applying colors
canada_map <- fortify(canada, region="CDNAME")

# merge in areas
canada_map <- merge(canada_map, map_areas, by="id")

gg <- ggplot()
gg <- gg + geom_map(data=canada_map, map=canada_map,
                    aes(map_id=id, x=long, y=lat, group=group, fill=log1p(area)),
                    color="white", size=0.1)
gg <- gg + coord_map() # can choose other projections
gg <- gg + theme_map()
gg

但是，我遇到了几个错误。第一个是：

system("ogr2ogr canada.shp gcd_000b11a_e.shp -simplify 0.01")
/bin/sh: ogr2ogr: command not found

搜索并阅读了一些想法（例如here 和here）后，我发现rgdal 有问题。我可以加载rgdal库没问题：

> library(rgdal)
> 

但后来我查找目录/Macintosh HD/Library/Frameworks，并没有GDAL_Frameworks子目录。

我正在运行 Mac OSX Sierra，版本 10.12.6 和 R 版本 3.4.1（单蜡烛）。

如何正确运行system 命令？

Answer 1

如果这只是 Mac 系统路径的问题，您也可以提供 gdal 库的完整路径。

system("/Library/Frameworks/GDAL.framework/Programs/ogr2ogr canada.shp gcd_000b11a_e.shp -simplify 0.01")

上面的路径也可能是错误的，要获得正确的路径在Mac终端运行which ogr2ogr。如果此路径与/Library/Frameworks/GDAL.framework/Programs/ogr2ogr 不同，请使用正确的路径。

如果您仍然对 gdal 库有问题，请尝试从源代码安装并再次在 R 中运行以上系统命令 brew install gdal-20 --build-from-source