geojsonio vignette

Scott Chamberlain

2019-10-29

geojsonio converts geographic data to geojson and topojson formats. Nothing else. We hope to do this one job very well, and handle all reasonable use cases.

Functions in this package are organized first around what you’re working with or want to get, geojson or topojson, then convert to or read from various formats:

• geojson_list()/topojson_list() - convert to GeoJSON/TopoJSON as R list format
• geojson_json()/topojson_json() - convert to GeoJSON/TopoJSON as JSON
• geojson_sp() - convert output of geojson_list() or geojson_json() to spatial objects
• geojson_read()/topojson_read() - read a GeoJSON/TopoJSON file from file path or URL
• geojson_write()/topojson_write() - write a GeoJSON/TopoJSON file locally

Each of the above functions have methods for various objects/classes, including numeric, data.frame, list, SpatialPolygons, SpatialLines, SpatialPoints, etc.

Additional functions:

• map_gist() - push up a geojson or topojson file as a GitHub gist (renders as an interactive map) - See the maps with geojsonio vignette.
• map_leaf() - create a local interactive map with the leaflet package - See the maps with geojsonio vignette.

install.packages("http://cran.r-project.org/src/contrib/rgdal_1.1-3.tar.gz", repos = NULL, type="source", configure.args = "--with-gdal-config=/Library/Frameworks/GDAL.framework/Versions/1.11/unix/bin/gdal-config --with-proj-include=/Library/Frameworks/PROJ.framework/unix/include --with-proj-lib=/Library/Frameworks/PROJ.framework/unix/lib")

install.packages("geojsonio")

devtools::install_github("ropensci/geojsonio")

library("geojsonio")

geojson_json(c(32.45, -99.74))

geojson_list(c(32.45, -99.74))

library('maps')
data(us.cities)
geojson_json(us.cities[1:2, ], lat = 'lat', lon = 'long')

geojson_list(us.cities[1:2, ], lat = 'lat', lon = 'long')

library('sp')
poly1 <- Polygons(list(Polygon(cbind(c(-100,-90,-85,-100),
  c(40,50,45,40)))), "1")
poly2 <- Polygons(list(Polygon(cbind(c(-90,-80,-75,-90),
  c(30,40,35,30)))), "2")
sp_poly <- SpatialPolygons(list(poly1, poly2), 1:2)

geojson_json(sp_poly)

geojson_list(sp_poly)

x <- c(1, 2, 3, 4, 5)
y <- c(3, 2, 5, 1, 4)
s <- SpatialPoints(cbind(x, y))

geojson_json(s)

geojson_list(s)

library('maps')
data(us.cities)
geojson_write(us.cities[1:2, ], lat = 'lat', lon = 'long')

library("sp")
file <- system.file("examples", "california.geojson", package = "geojsonio")
out <- geojson_read(file, what = "sp")
plot(out)

topojson_json(c(-99.74,32.45))

library(sp)
x <- c(1,2,3,4,5)
y <- c(3,2,5,1,4)
s <- SpatialPoints(cbind(x,y))
topojson_list(s)

file <- system.file("examples", "us_states.topojson", package = "geojsonio")
out <- topojson_read(file, verbose = FALSE)
summary(out)

url <- "https://raw.githubusercontent.com/shawnbot/d3-cartogram/master/data/us-states.topojson"
out <- topojson_read(url, verbose = FALSE)

(loc <- as.location(file))
out <- topojson_read(loc, verbose = FALSE)