Type: Package
Title: GeoJSON to Simple Feature Converter
Version: 2.0.3
Date: 2022-05-31
Description: Converts Between GeoJSON and simple feature objects.
License: MIT + file LICENSE
URL: https://github.com/SymbolixAU/geojsonsf
BugReports: https://github.com/SymbolixAU/geojsonsf/issues
Encoding: UTF-8
LazyData: true
Depends: R (≥ 3.3.0)
SystemRequirements: C++11
LinkingTo: geometries, jsonify (≥ 1.1.1), rapidjsonr (≥ 1.2.0), Rcpp, sfheaders (≥ 0.2.2)
Imports: Rcpp
RoxygenNote: 7.1.0
Suggests: covr, jsonify, knitr, rmarkdown, tinytest
VignetteBuilder: knitr
NeedsCompilation: yes
Packaged: 2022-05-30 22:52:38 UTC; david
Author: David Cooley [aut, cre]
Maintainer: David Cooley <dcooley@symbolix.com.au>
Repository: CRAN
Date/Publication: 2022-05-30 23:20:02 UTC

df to GeoJSON

Description

Converts data.frame objects to GeoJSON. Each row is considerd a POINT

Usage

df_geojson(
  df,
  lon,
  lat,
  z = NULL,
  m = NULL,
  atomise = FALSE,
  simplify = TRUE,
  digits = NULL,
  factors_as_string = TRUE
)

Arguments

df

data.frame

lon

column of df containing the longitude data

lat

column of df containing the latitude data

z

column of df containing the Z attribute of the GeoJSON

m

column of df containing the M attribute of the GeoJSON. If supplied, you must also supply z

atomise

logical indicating if the data.frame should be converted into a vector of GeoJSON objects

simplify

logical indicating if data.frame without property columns should simplify (TRUE) into a vector of GeoJSON, or (FALSE). If atomise is TRUE this argument is ignored.

digits

integer specifying the number of decimal places to round numerics. numeric values are coorced using as.integer, which may round-down the value you supply. Default is NULL - no rounding

factors_as_string

logical indicating if factors should be treated as strings. Defaults to TRUE.

Value

vector of GeoJSON

Examples


df <- data.frame(lon = c(1:5, NA), lat = c(1:5, NA), id = 1:6, val = letters[1:6])
df_geojson( df, lon = "lon", lat = "lat")
df_geojson( df, lon = "lon", lat = "lat", atomise = TRUE)

df <- data.frame(lon = c(1:5, NA), lat = c(1:5, NA) )
df_geojson( df, lon = "lon", lat = "lat")
df_geojson( df, lon = "lon", lat = "lat", simplify = FALSE)

df <- data.frame(lon = c(1:5), lat = c(1:5), elevation = c(1:5) )
df_geojson( df, lon = "lon", lat = "lat", z = "elevation")
df_geojson( df, lon = "lon", lat = "lat", z = "elevation", simplify = FALSE)

df <- data.frame(lon = c(1:5), lat = c(1:5), elevation = c(1:5), id = 1:5 )
df_geojson( df, lon = "lon", lat = "lat", z = "elevation")
df_geojson( df, lon = "lon", lat = "lat", z = "elevation", atomise = TRUE)


## to sf objects
geo <- df_geojson( df, lon = "lon", lat = "lat", z = "elevation")
sf <- geojson_sf( geo )

geo_melbourne

Description

GeoJSON data of Melbourne's Inner suburbs.

Usage

geo_melbourne

Format

An object of class geojson (inherits from json) of length 1.

Geojson to sf

Description

Converts GeoJSON to an 'sf' object

Usage

geojson_sf(
  geojson,
  expand_geometries = FALSE,
  input = NULL,
  wkt = NULL,
  crs = NULL,
  proj4string = NULL,
  buffer_size = 1024
)

Arguments

geojson

string or vector of GeoJSON, or a URL or file pointing to a geojson file

expand_geometries

logical indicating whether to unnest GEOMETRYCOLLECTION rows. see details

input

user input for coordinate reference system object

wkt

well-known text for coordinate reference system object

crs

deprecated. coordinate reference system. See Details

proj4string

deprecated. proj4string. See Details

buffer_size

size of buffer used when reading a file from disk. Defaults 1024

Details

specifying expand_geometries = TRUE will expand individual GEOMETRYCOLLECTION geometries to their own row in the resulting 'sf' object. If the geometries are part of a Feature (i.e., with properties), the properties will be repeated on each row.

The GEOMETRYCOLLECTION information is not kept when using expand_geometries = TRUE. Therefore, it is not possible to reconstruct the GEOMETRYCOLLECTION after unnesting it.

Geojson specification RFC7946 https://tools.ietf.org/html/rfc7946#page-12 says all CRS should be the World Geodetic System 1984 (WGS 84) [WGS84] datum, with longitude and latitude units of decimal degrees. This is equivalent to the coordinate reference system identified by the Open Geospatial Consortium (OGC) URN urn:ogc:def:crs:OGC::CRS84

geojson_sfc and geojson_sf automatically set the CRS to WGS 84. The fields input and wkt let you to overwrite the defaults.

Examples


## character string of GeoJSON

## load 'sf' for print methods
# library(sf)
geojson <- '{ "type" : "Point", "coordinates" : [0, 0] }'
geojson_sf(geojson)


## Not run: 
## GeoJSON at a url
myurl <- "http://eric.clst.org/assets/wiki/uploads/Stuff/gz_2010_us_050_00_500k.json"
sf <- geojson_sf(myurl)

## End(Not run)

Geojson to sfc

Description

Extracts geometries from GeoJSON and returns an 'sfc' object

Usage

geojson_sfc(
  geojson,
  expand_geometries = FALSE,
  input = NULL,
  wkt = NULL,
  crs = NULL,
  proj4string = NULL,
  buffer_size = 1024
)

Arguments

geojson

string or vector of GeoJSON, or a URL or file pointing to a geojson file

expand_geometries

logical indicating whether to unnest GEOMETRYCOLLECTION rows. see details

input

user input for coordinate reference system object

wkt

well-known text for coordinate reference system object

crs

deprecated. coordinate reference system. See Details

proj4string

deprecated. proj4string. See Details

buffer_size

size of buffer used when reading a file from disk. Defaults 1024

Details

specifying expand_geometries = TRUE will expand individual GEOMETRYCOLLECTION geometries to their own row in the resulting 'sf' object. If the geometries are part of a Feature (i.e., with properties), the properties will be repeated on each row.

The GEOMETRYCOLLECTION information is not kept when using expand_geometries = TRUE. Therefore, it is not possible to reconstruct the GEOMETRYCOLLECTION after unnesting it.

Geojson specification RFC7946 https://tools.ietf.org/html/rfc7946#page-12 says all CRS should be the World Geodetic System 1984 (WGS 84) [WGS84] datum, with longitude and latitude units of decimal degrees. This is equivalent to the coordinate reference system identified by the Open Geospatial Consortium (OGC) URN urn:ogc:def:crs:OGC::CRS84

geojson_sfc and geojson_sf automatically set the CRS to WGS 84. The fields input and wkt let you to overwrite the defaults.

Examples


## character string of GeoJSON

## load 'sf' for print methods
# library(sf)
geojson <- '{ "type":"Point","coordinates":[0,0] }'
geojson_sfc(geojson)

geojson <- '[
  { "type":"Point","coordinates":[0,0]},
  {"type":"LineString","coordinates":[[0,0],[1,1]]}
  ]'
geojson_sfc( geojson )

## Not run: 
## GeoJSON at a url
myurl <- "http://eric.clst.org/assets/wiki/uploads/Stuff/gz_2010_us_050_00_500k.json"
sf <- geojson_sfc(myurl)

## End(Not run)

Geojson to WKT

Description

Converts GeoJSON to Well-Known Text

Usage

geojson_wkt(geojson)

Arguments

geojson

string or vector of GeoJSON, or a URL or file pointing to a geojson file

Value

data.frame with a 'geometry' column of well-known text

Examples

geojson <- '{ "type" : "Point", "coordinates" : [0, 0] }'
geojson_wkt(geojson)

sf to GeoJSON

Description

Converts 'sf' objects to GeoJSON

Usage

sf_geojson(
  sf,
  atomise = FALSE,
  simplify = TRUE,
  digits = NULL,
  factors_as_string = TRUE
)

Arguments

sf

simple feature object

atomise

logical indicating if the sf object should be converted into a vector of GeoJSON objects

simplify

logical indicating if sf objects without property columns should simplify (TRUE) into a vector of GeoJSON, or return a Featurecollection with empty property fields (FALSE). If atomise is TRUE this argument is ignored.

digits

integer specifying the number of decimal places to round numerics. numeric values are coorced using as.integer, which may round-down the value you supply. Default is NULL - no rounding

factors_as_string

logical indicating if factors should be treated as strings. Defaults to TRUE.

Value

vector of GeoJSON

Examples

## Not run: 
library(sf)
sf <- sf::st_sf(geometry = sf::st_sfc(list(sf::st_point(c(0,0)), sf::st_point(c(1,1)))))
sf$id <- 1:2
sf_geojson(sf)
sf_geojson(sf, atomise = T)

ls <- st_linestring(rbind(c(0,0),c(1,1),c(2,1)))
mls <- st_multilinestring(list(rbind(c(2,2),c(1,3)), rbind(c(0,0),c(1,1),c(2,1))))
sfc <- st_sfc(ls,mls)
sf <- st_sf(sfc)
sf_geojson( sf )
sf_geojson( sf, simplify = FALSE )


## End(Not run)

sfc to GeoJSON

Description

Converts 'sfc' objects to GeoJSON

Usage

sfc_geojson(sfc, digits = NULL)

Arguments

sfc

simple feature collection object

digits

integer specifying the number of decimal places to round numeric coordinates. numeric values are coorced using as.integer, which may round-down the value you supply. Default is NULL - no rounding

Value

vector of GeoJSON

Examples

## Not run: 
library(sf)
sf <- sf::st_sfc(list(sf::st_point(c(0,0)), sf::st_point(c(1,1))))
sfc_geojson(sf)

## End(Not run)