Support for NULL/empty geoJSON points.

[SimonGoring]

The RFC allows for empty geoJSON objects link:

RFC 7946


3.1.  Geometry Object

   o  A GeoJSON Geometry object of any type other than "GeometryCollection" has a member with the name "coordinates". The value of the "coordinates" member is an array.  The structure of the elements in this array is determined by the type of geometry.  GeoJSON processors MAY interpret Geometry objects with empty "coordinates" arrays as null objects.

Currently the following fails:

> geojson_sf('{
  "type": "FeatureCollection",
  "features": [
    { "type": "Feature", "properties": null, "geometry": {"type":"Point","coordinates":[]} } 
  ]}')

Error in rcpp_geojson_to_sf(geojson, expand_geometries) : 
  Invalid lon/lat object

Is this something that can be fixed?

---

TODO:

• geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"Point","coordinates":[]} }')
• geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"MultiPoint","coordinates":[]}}')
• geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"LineString","coordinates":[]}}')
• geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"MultiLineString","coordinates":[]}}')
• geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"Polygon","coordinates":[]}}')
• geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"MultiPolygon","coordinates":[]}}')
• geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type": "GeometryCollection", "geometries":[{"type":"Point","coordinates":[]},{"type":"LineString","coordinates":[]}]}}')
• geojson <- '{ "type": "FeatureCollection", "features": [ { "type": "Feature", "properties": null, "geometry": {"type":"Point","coordinates":[]} }, { "type": "Feature", "properties": null, "geometry": {"type":"MultiPoint","coordinates":[]} }, { "type": "Feature", "properties": null, "geometry": {"type":"LineString","coordinates":[]} }, { "type": "Feature", "properties": null, "geometry": {"type":"MultiLineString","coordinates":[]} }, { "type": "Feature", "properties": null, "geometry": {"type":"Polygon","coordinates":[]} }, { "type": "Feature", "properties": null, "geometry": {"type":"MultiPolygon","coordinates":[]} } ]}'

---

• round trip

geo <- '{
  "type": "FeatureCollection",
  "features": [
  { "type": "Feature", "properties": null, "geometry": {"type":"Point","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"MultiPoint","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"LineString","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"MultiLineString","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"Polygon","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"MultiPolygon","coordinates":[]} },
	{ "type": "Feature", "properties": null, "geometry": {"type": "GeometryCollection", "geometries":[{"type":"Point","coordinates":[]},{"type":"LineString","coordinates":[]}]}}
  ]}'


sf <- geojsonsf::geojson_sf(geo)
geo <- geojsonsf::sf_geojson(sf)

[dcooley]

yes that should be do-able. As an interim solution you can use sf directly to read the geojson

library(sf)

sf <- sf::st_read(
  '{
  "type": "FeatureCollection",
  "features": [
    { "type": "Feature", "properties": null, "geometry": {"type":"Point","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"Point","coordinates":[1.0, 1.0]} }
  ]}'
)

sf

# Simple feature collection with 2 features and 0 fields (with 1 geometry empty)
# Geometry type: POINT
# Dimension:     XY
# Bounding box:  xmin: 1 ymin: 1 xmax: 1 ymax: 1
# Geodetic CRS:  WGS 84
# geometry
# 1 POINT EMPTY
# 2 POINT (1 1)

[dcooley]

On branch issue91 these examples now work

library(sf)
library(geojsonsf)

geojson <- 	'{
  "type": "FeatureCollection",
  "features": [
  { "type": "Feature", "properties": null, "geometry": {"type":"Point","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"MultiPoint","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"LineString","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"MultiLineString","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"Polygon","coordinates":[]} },
  { "type": "Feature", "properties": null, "geometry": {"type":"MultiPolygon","coordinates":[]} }
  ]}'


geojsonsf::geojson_sf(geojson)

geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"Point","coordinates":[]} }')
geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"MultiPoint","coordinates":[]}}')
geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"LineString","coordinates":[]}}')
geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"MultiLineString","coordinates":[]}}')
geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"Polygon","coordinates":[]}}')
geojson_sf('{ "type": "Feature", "properties": null, "geometry": {"type":"MultiPolygon","coordinates":[]}}')