geojsonio

Convert various data formats to GeoJSON or TopoJSON

This package is a utility to convert 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 sp spatial objects
geojson_sf() - convert output of geojson_list() or geojson_json() to sf 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)
map_leaf() - create a local interactive map using the leaflet package

*json Info

GeoJSON - spec
GeoJSON lint
TopoJSON - spec

Install

A note about installing rgeos - built on top of C libraries, and installation often causes trouble for Linux users because no binaries are provided on CRAN for those platforms. Other dependencies in geojsonio should install easily automatically when you install geojsonio.

Mac

Install GDAL on the command line first, e.g., using homebrew

brew install gdal

Then install rgeos

install.packages("rgeos", type = "source")

Linux

Get deps first

sudo apt-get install libgdal1-dev libgdal-dev libgeos-c1 libproj-dev

Note: if you have trouble installing rgeos, try installing libgeos++-dev

Then install rgeos

install.packages("rgeos", type = "source")

Install geojsonio

Stable version from CRAN

install.packages("geojsonio")

Or development version from GitHub

install.packages("devtools")
devtools::install_github("ropensci/geojsonio")

library("geojsonio")

GeoJSON

Convert various formats to GeoJSON

From a numeric vector of length 2, as json or list

geojson_json(c(32.45, -99.74))
#> <FeatureCollection> 
#>   type:  FeatureCollection 
#>   no. features:  1 
#>   features (1st 5):  Point

geojson_list(c(32.45, -99.74))
#> $type
#> [1] "FeatureCollection"
#> 
#> $features
#> $features[[1]]
#> $features[[1]]$type
#> [1] "Feature"
#> 
#> $features[[1]]$geometry
#> $features[[1]]$geometry$type
...

From a data.frame

library('maps')
data(us.cities)
geojson_json(us.cities[1:2, ], lat = 'lat', lon = 'long')
#> <FeatureCollection> 
#>   type:  FeatureCollection 
#>   no. features:  2 
#>   features (1st 5):  Point, Point

geojson_list(us.cities[1:2, ], lat = 'lat', lon = 'long')
#> $type
#> [1] "FeatureCollection"
#> 
#> $features
#> $features[[1]]
#> $features[[1]]$type
#> [1] "Feature"
#> 
#> $features[[1]]$geometry
#> $features[[1]]$geometry$type
...

From SpatialPolygons class

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)

to json

geojson_json(sp_poly)
#> <FeatureCollection> 
#>   type:  FeatureCollection 
#>   no. features:  2 
#>   features (1st 5):  Polygon, Polygon

to list

geojson_list(sp_poly)$features[[1]]
#> $type
#> [1] "Feature"
#> 
#> $id
#> [1] 1
#> 
#> $properties
#> $properties$dummy
#> [1] 0
#> 
...

Combine objects

geo_list + geo_list

Note: geo_list is the output type from geojson_list(), it’s just a list with a class attached so we know it’s geojson :)

vec <- c(-99.74, 32.45)
a <- geojson_list(vec)
vecs <- list(c(100.0, 0.0), c(101.0, 0.0), c(100.0, 0.0))
b <- geojson_list(vecs, geometry = "polygon")
a + b
#> $type
#> [1] "FeatureCollection"
#> 
#> $features
#> $features[[1]]
#> $features[[1]]$type
#> [1] "Feature"
#> 
#> $features[[1]]$geometry
#> $features[[1]]$geometry$type
...

json + json

c <- geojson_json(c(-99.74, 32.45))
vecs <- list(c(100.0, 0.0), c(101.0, 0.0), c(101.0, 1.0), c(100.0, 1.0), c(100.0, 0.0))
d <- geojson_json(vecs, geometry = "polygon")
c + d
#> {"type":"FeatureCollection","features":[{"type":"Feature","geometry":{"type":"Point","coordinates":[-99.74,32.45]},"properties":{}},{"type":"Feature","geometry":{"type":"Polygon","coordinates":[[[100,0],[101,0],[101,1],[100,1],[100,0]]]},"properties":[]}]}

Write GeoJSON

library('maps')
data(us.cities)
geojson_write(us.cities[1:2, ], lat = 'lat', lon = 'long')
#> <geojson-file>
#>   Path:       myfile.geojson
#>   From class: data.frame

Read GeoJSON

file <- system.file("examples", "california.geojson", package = "geojsonio")
out <- geojson_read(file)
names(out)
#> [1] "type"     "name"     "crs"      "features"
names(out$features[[1]])
#> [1] "type"       "properties" "geometry"

TopoJSON

to JSON

topojson_json(c(-99.74,32.45))
#> {"type":"Topology","objects":{"foo":{"type":"GeometryCollection","geometries":[{"type":"Point","coordinates":[-99.74,32.45]}]}},"arcs":[],"bbox":[-99.74,32.45,-99.74,32.45]}

to list

library(sp)
x <- c(1,2,3,4,5)
y <- c(3,2,5,1,4)
s <- SpatialPoints(cbind(x,y))
topojson_list(s)
#> $type
#> [1] "Topology"
#> 
#> $objects
#> $objects$foo
#> $objects$foo$type
#> [1] "GeometryCollection"
#> 
#> $objects$foo$geometries
#> $objects$foo$geometries[[1]]
#> $objects$foo$geometries[[1]]$type
#> [1] "Point"
#> 
#> $objects$foo$geometries[[1]]$coordinates
#> [1] 1 3
#> 
#> $objects$foo$geometries[[1]]$id
#> [1] 1
#> 
#> $objects$foo$geometries[[1]]$properties
...

Write TopoJSON

library('maps')
data(us.cities)
topojson_write(us.cities[1:2, ], lat = 'lat', lon = 'long')
#> <topojson-file>
#>   Path:       myfile.topojson
#>   From class: data.frame

Read TopoJSON

file <- system.file("examples", "us_states.topojson", package = "geojsonio")
out <- topojson_read(file)
#> Reading layer `states' from data source `/Library/Frameworks/R.framework/Versions/3.6/Resources/library/geojsonio/examples/us_states.topojson' using driver `TopoJSON'
#> Simple feature collection with 51 features and 1 field
#> geometry type:  MULTIPOLYGON
#> dimension:      XY
#> bbox:           xmin: -171.7911 ymin: 18.91619 xmax: -66.96466 ymax: 71.35776
#> epsg (SRID):    NA
#> proj4string:    NA
plot(out)

Use case: Play with US states

Using data from https://github.com/glynnbird/usstatesgeojson

Get some geojson

library('crul')
res <- HttpClient$new('https://api.github.com')$get('repos/glynnbird/usstatesgeojson/contents')
out <- jsonlite::fromJSON(res$parse("UTF-8"), FALSE)
st_names <- Filter(function(x) grepl("\\.geojson", x), sapply(out, "[[", "name"))
base <- 'https://raw.githubusercontent.com/glynnbird/usstatesgeojson/master/'
st_files <- paste0(base, st_names)

Make a faceted plot

library('ggplot2')
library('plyr')
st_use <- st_files[7:13]
geo <- lapply(st_use, geojson_read, what = "sp")
df <- ldply(setNames(lapply(geo, fortify), gsub("\\.geojson", "", st_names[7:13])))
ggplot(df, aes(long, lat, group = group)) +
  geom_polygon() +
  facet_wrap(~.id, scales = "free")

Okay, so the maps are not quite right (stretched to fit each panel), but you get the idea.

GeoJSON <-> TopoJSON

geo2topo() and topo2geo()

x <- '{"type": "LineString", "coordinates": [ [100.0, 0.0], [101.0, 1.0] ]}'
(topo_json <- geo2topo(x))
#> {"type":"Topology","objects":{"foo":{"type":"LineString","arcs":[0]}},"arcs":[[[100,0],[101,1]]],"bbox":[100,0,101,1]}
topo2geo(topo_json)
#> <FeatureCollection> 
#>   type:  FeatureCollection 
#>   no. features:  1 
#>   features (1st 5):  LineString

geojsonio

*json Info

Install

GeoJSON

Convert various formats to GeoJSON

Combine objects

Write GeoJSON

Read GeoJSON

TopoJSON

to JSON

to list

Write TopoJSON

Read TopoJSON

Use case: Play with US states

GeoJSON <-> TopoJSON

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