There are various flavors of newline-delimited GeoJSON, all of which we aim to handle here. See Details for more.
Usage
ndgeo_write(x, file, sep = "\n")
# Default S3 method
ndgeo_write(x, file, sep = "\n")
# S3 method for class 'geofeaturecollection'
ndgeo_write(x, file, sep = "\n")
# S3 method for class 'geofeature'
ndgeo_write(x, file, sep = "\n")
ndgeo_read(txt, pagesize = 500, verbose = TRUE)Arguments
- x
input, an object of class
geojson- file
(character) a file. not a connection. required.
- sep
(character) a character separator to use in
writeLines()- txt
text, a file, or a url. required.
- pagesize
(integer) number of lines to read/write from/to the connection per iteration
- verbose
(logical) print messages. default:
TRUE
Details
ndgeo_write: writes geojson package types as newline-delimited GeoJSON to a filendgeo_read: reads newline-delimited GeoJSON from a string, file, or URL into the appropriate geojson type
As an alternative to ndgeo_read, you can simply use
jsonlite::stream_in() to convert newline-delimited GeoJSON
to a data.frame
Note
IMPORTANT: ngeo_read for now only handles lines of geojson
in your file that are either features or geometry objects (e.g., point,
multipoint, polygon, multipolygon, linestring, multilinestring)
References
Newline-delimited JSON has a few flavors. The only difference between ndjson http://ndjson.org/ and JSON Lines https://jsonlines.org/ I can tell is that the former requires UTF-8 encoding, while the latter does not.
GeoJSON text sequences has a specification found at https://datatracker.ietf.org/doc/html/rfc8142. The spec states that:
a GeoJSON text sequence is any number of GeoJSON RFC7946 texts
each line encoded in UTF-8 RFC3629
each line preceded by one ASCII RFC20 record separator (RS; "0x1e") character
each line followed by a line feed (LF)
each JSON text MUST contain a single GeoJSON object as defined in RFC7946
See also the GeoJSON specification https://datatracker.ietf.org/doc/html/rfc7946
Examples
# featurecollection
## write
file <- system.file("examples", 'featurecollection2.geojson',
package = "geojson")
str <- paste0(readLines(file), collapse = " ")
(x <- featurecollection(str))
#> <FeatureCollection>
#> type: FeatureCollection
#> no. features: 3
#> features (1st 5): Point, Point, Point
outfile <- tempfile(fileext = ".geojson")
ndgeo_write(x, outfile)
readLines(outfile)
#> [1] "{\"type\":\"Feature\",\"id\":0,\"properties\":{\"NOME\":\"Sec de segunrança\",\"URL\":\"http://www.theatermania.com/new-york/theaters/45th-street-theatre_2278/\",\"ADDRESS1\":\"354 West 45th Street\",\"CIDADE\":\"Goiânia\",\"CEP\":74250010},\"geometry\":{\"type\":\"Point\",\"coordinates\":[-49.256240,-16.689612]}}"
#> [2] "{\"type\":\"Feature\",\"id\":1,\"properties\":{\"NOME\":\"Teste\",\"URL\":\"http://www.bestofoffbroadway.com/theaters/47streettheatre.html\",\"ADDRESS1\":\"304 West 47th Street\",\"CIDADE\":\"New York\",\"ZIP\":74250010},\"geometry\":{\"type\":\"Point\",\"coordinates\":[-49.276240,-16.655612]}}"
#> [3] "{\"type\":\"Feature\",\"id\":3,\"properties\":{\"NOME\":\"Delacorte Theater\",\"URL\":\"http://www.centralpark.com/pages/attractions/delacorte-theatre.html\",\"ADDRESS1\":\"Central Park - Mid-Park at 80th Street\",\"CIDADE\":\"New York\",\"ZIP\":74250010},\"geometry\":{\"type\":\"Point\",\"coordinates\":[-49.277263,-16.679057]}}"
jsonlite::stream_in(file(outfile))
#> opening file input connection.
#>
Found 3 records...
Imported 3 records. Simplifying...
#> closing file input connection.
#> type id properties.NOME
#> 1 Feature 0 Sec de segunrança
#> 2 Feature 1 Teste
#> 3 Feature 3 Delacorte Theater
#> properties.URL
#> 1 http://www.theatermania.com/new-york/theaters/45th-street-theatre_2278/
#> 2 http://www.bestofoffbroadway.com/theaters/47streettheatre.html
#> 3 http://www.centralpark.com/pages/attractions/delacorte-theatre.html
#> properties.ADDRESS1 properties.CIDADE properties.CEP
#> 1 354 West 45th Street Goiânia 74250010
#> 2 304 West 47th Street New York NA
#> 3 Central Park - Mid-Park at 80th Street New York NA
#> properties.ZIP geometry.type geometry.coordinates
#> 1 NA Point -49.25624, -16.68961
#> 2 74250010 Point -49.27624, -16.65561
#> 3 74250010 Point -49.27726, -16.67906
## read
ndgeo_read(outfile)
#> opening file input connection.
#>
Found 3 records...
#> closing file input connection.
#> <geojson>
#> type: FeatureCollection
#> features (n): 3
#> features (geometry / length) [first 5]:
#> Point / 2
#> Point / 2
#> Point / 2
unlink(outfile)
# read from an existing file
## GeoJSON objects all of same type: Feature
file <- system.file("examples", 'ndgeojson1.json', package = "geojson")
ndgeo_read(file)
#> opening file input connection.
#>
Found 3 records...
#> closing file input connection.
#> <geojson>
#> type: FeatureCollection
#> features (n): 3
#> features (geometry / length) [first 5]:
#> Point / 2
#> Point / 2
#> Point / 2
## GeoJSON objects all of same type: Point
file <- system.file("examples", 'ndgeojson2.json', package = "geojson")
ndgeo_read(file)
#> opening file input connection.
#>
Found 3 records...
#> closing file input connection.
#> <geojson>
#> type: FeatureCollection
#> features (n): 3
#> features (geometry / length) [first 5]:
#> Point / 2
#> Point / 2
#> Point / 2
## GeoJSON objects of mixed type: Point, and Feature
file <- system.file("examples", 'ndgeojson3.json', package = "geojson")
ndgeo_read(file)
#> opening file input connection.
#>
Found 3 records...
#> closing file input connection.
#> <geojson>
#> type: FeatureCollection
#> features (n): 3
#> features (geometry / length) [first 5]:
#> Point / 2
#> Point / 2
#> Point / 2
if (FALSE) { # \dontrun{
# read from a file
url <- "https://raw.githubusercontent.com/ropensci/geojson/main/inst/examples/ndgeojson1.json"
f <- tempfile(fileext = ".geojsonl")
download.file(url, f)
x <- ndgeo_read(f)
x
unlink(f)
# read from a URL
url <- "https://raw.githubusercontent.com/ropensci/geojson/main/inst/examples/ndgeojson1.json"
x <- ndgeo_read(url)
x
# geojson text sequences from file
file <- system.file("examples", 'featurecollection2.geojson',
package = "geojson")
str <- paste0(readLines(file), collapse = " ")
x <- featurecollection(str)
outfile <- tempfile(fileext = ".geojson")
ndgeo_write(x, outfile, sep = "\u001e\n")
con <- file(outfile)
readLines(con)
close(con)
ndgeo_read(outfile)
unlink(outfile)
} # }