There are various flavors of newline-delimited GeoJSON, all of which we aim to handle here. See Details for more.
ndgeo_write(x, file, sep = "\n") # S3 method for default ndgeo_write(x, file, sep = "\n") # S3 method for geofeaturecollection ndgeo_write(x, file, sep = "\n") # S3 method for geofeature ndgeo_write(x, file, sep = "\n") ndgeo_read(txt, pagesize = 500, verbose = TRUE)
Arguments
| x | input, an object of class |
|---|---|
| file | (character) a file. not a connection. required. |
| sep | (character) a character separator to use in |
| 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: |
Value
a geojson class object
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 http://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://tools.ietf.org/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://tools.ietf.org/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#> [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\":[-49.25624,-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\":[-49.27624,-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]}}"#>#> Found 3 records... Imported 3 records. Simplifying...#>#> 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)#>#> Found 3 records...#>#> <geojson> #> type: FeatureCollection #> features (n): 3 #> features (geometry / length) [first 5]: #> Point / 2 #> Point / 2 #> Point / 2unlink(outfile) # read from an existing file ## GeoJSON objects all of same type: Feature file <- system.file("examples", 'ndgeojson1.json', package = "geojson") ndgeo_read(file)#>#> Found 3 records...#>#> <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)#>#> Found 3 records...#>#> <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)#>#> Found 3 records...#>#> <geojson> #> type: FeatureCollection #> features (n): 3 #> features (geometry / length) [first 5]: #> Point / 2 #> Point / 2 #> Point / 2if (FALSE) { # read from a file url <- "https://raw.githubusercontent.com/ropensci/geojson/master/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/master/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) }