README

geojson aims to deal only with geojson data, without requiring any of the sp/rgdal/rgeos stack. That means this package is light weight.

We’ve defined classes (S3) following the GeoJSON spec. These classes sort of overlap with sp’s classes, but not really. There’s also some overlap in GeoJSON classes with Well-Known Text (WKT) classes, but GeoJSON has a subset of WKT’s classes.

The package geoops supports manipulations on the classes defined in this package. This package is used within geojsonio to make some tasks easier.

Installation

install.packages("geojson")

devtools::install_github("ropensci/geojson")

library("geojson")

geojson class

Essentially a character string with S3 class geojson attached to make it easy to perform operations on

x <- "{\"type\":\"FeatureCollection\",\"features\":[{\"type\":\"Feature\",\"geometry\":{\"type\":\"Point\",\"coordinates\":[-99.74,32.45]},\"properties\":{}}]}"
as.geojson(x)
#> <geojson> 
#>   type:  FeatureCollection 
#>   bounding box:  99.74 32.45 99.74 32.45 
#>   features (n): 1 
#>   features (geometry / length):
#>     Point / 2

geometrycollection

x <- '{
 "type": "GeometryCollection",
 "geometries": [
   {
     "type": "Point",
     "coordinates": [100.0, 0.0]
   },
   {
     "type": "LineString",
     "coordinates": [ [101.0, 0.0], [102.0, 1.0] ]
   }
  ]
}'
(y <- geometrycollection(x))
#> <GeometryCollection> 
#>   geometries (n): 2 
#>   geometries (geometry / length):
#>     Point / 2
#>     LineString / 2

inspect the object

y[[1]]
#> [1] "{\n \"type\": \"GeometryCollection\",\n \"geometries\": [\n   {\n     \"type\": \"Point\",\n     \"coordinates\": [100.0, 0.0]\n   },\n   {\n     \"type\": \"LineString\",\n     \"coordinates\": [ [101.0, 0.0], [102.0, 1.0] ]\n   }\n  ]\n}"

geo_type(y)
#> [1] "GeometryCollection"

geo_pretty(y)
#> {
#>     "type": "GeometryCollection",
#>     "geometries": [
#>         {
#>             "type": "Point",
#>             "coordinates": [
#>                 100.0,
#>                 0.0
#>             ]
#>         },
#>         {
#>             "type": "LineString",
#>             "coordinates": [
#>                 [
#>                     101.0,
#>                     0.0
#>                 ],
#>                 [
#>                     102.0,
#>                     1.0
#>                 ]
#>             ]
#>         }
#>     ]
#> }
#>

geo_write(y, f <- tempfile(fileext = ".geojson"))
jsonlite::fromJSON(f, FALSE)
#> $type
#> [1] "GeometryCollection"
#> 
#> $geometries
#> $geometries[[1]]
#> $geometries[[1]]$type
#> [1] "Point"
#> 
#> $geometries[[1]]$coordinates
#> $geometries[[1]]$coordinates[[1]]
#> [1] 100
#> 
#> $geometries[[1]]$coordinates[[2]]
#> [1] 0
#> 
#> 
#> 
#> $geometries[[2]]
#> $geometries[[2]]$type
#> [1] "LineString"
#> 
#> $geometries[[2]]$coordinates
#> $geometries[[2]]$coordinates[[1]]
#> $geometries[[2]]$coordinates[[1]][[1]]
#> [1] 101
#> 
#> $geometries[[2]]$coordinates[[1]][[2]]
#> [1] 0
#> 
#> 
#> $geometries[[2]]$coordinates[[2]]
#> $geometries[[2]]$coordinates[[2]][[1]]
#> [1] 102
#> 
#> $geometries[[2]]$coordinates[[2]][[2]]
#> [1] 1

properties

x <- '{ "type": "LineString", "coordinates": [ [100.0, 0.0], [101.0, 1.0] ]}'
res <- linestring(x) %>% feature() %>% properties_add(population = 1000)
res
#> <Feature> 
#>   type:  LineString 
#>   coordinates:  [[100,0],[101,1]]

properties_get(res, property = 'population')
#> 1000

crs

crs <- '{
  "type": "name",
  "properties": {
     "name": "urn:ogc:def:crs:OGC:1.3:CRS84"
  }
}'
z <- x %>% feature() %>% crs_add(crs)
z
#> {
#>     "type": "Feature",
#>     "properties": {
#> 
#>     },
#>     "geometry": {
#>         "type": "LineString",
#>         "coordinates": [
#>             [
#>                 100,
#>                 0
#>             ],
#>             [
#>                 101,
#>                 1
#>             ]
#>         ]
#>     },
#>     "crs": {
#>         "type": "name",
#>         "properties": {
#>             "name": "urn:ogc:def:crs:OGC:1.3:CRS84"
#>         }
#>     }
#> }

crs_get(z)
#> $type
#> [1] "name"
#> 
#> $properties
#> $properties$name
#> [1] "urn:ogc:def:crs:OGC:1.3:CRS84"

bbox

tt <- x %>% feature() %>% bbox_add()
tt
#> {
#>     "type": "Feature",
#>     "properties": {
#> 
#>     },
#>     "geometry": {
#>         "type": "LineString",
#>         "coordinates": [
#>             [
#>                 100,
#>                 0
#>             ],
#>             [
#>                 101,
#>                 1
#>             ]
#>         ]
#>     },
#>     "bbox": [
#>         100,
#>         0,
#>         101,
#>         1
#>     ]
#> }

bbox_get(tt)
#> [1] 100   0 101   1

geojson in data.frame’s

x <- '{ "type": "Point", "coordinates": [100.0, 0.0] }'
(pt <- point(x))
#> <Point> 
#>   coordinates:  [100,0]

library("tibble")
data_frame(a = 1:5, b = list(pt))
#> # A tibble: 5 x 2
#>       a              b
#>   <int>         <list>
#> 1     1 <S3: geopoint>
#> 2     2 <S3: geopoint>
#> 3     3 <S3: geopoint>
#> 4     4 <S3: geopoint>
#> 5     5 <S3: geopoint>

x <- '{ "type": "MultiLineString",
  "coordinates": [ [ [100.0, 0.0], [101.0, 1.0] ], [ [102.0, 2.0], [103.0, 3.0] ] ] }'
(mls <- multilinestring(x))
#> <MultiLineString> 
#>   no. lines:  2 
#>   no. nodes / line:  2, 2 
#>   coordinates:  [[[100,0],[101,1]],[[102,2],[103,3]]]

data_frame(a = 1:5, b = list(mls))
#> # A tibble: 5 x 2
#>       a                        b
#>   <int>                   <list>
#> 1     1 <S3: geomultilinestring>
#> 2     2 <S3: geomultilinestring>
#> 3     3 <S3: geomultilinestring>
#> 4     4 <S3: geomultilinestring>
#> 5     5 <S3: geomultilinestring>

data_frame(a = 1:5, b = list(pt), c = list(mls))
#> # A tibble: 5 x 3
#>       a              b                        c
#>   <int>         <list>                   <list>
#> 1     1 <S3: geopoint> <S3: geomultilinestring>
#> 2     2 <S3: geopoint> <S3: geomultilinestring>
#> 3     3 <S3: geopoint> <S3: geomultilinestring>
#> 4     4 <S3: geopoint> <S3: geomultilinestring>
#> 5     5 <S3: geopoint> <S3: geomultilinestring>

geojson