I created a GeoJSON extraction interface for Smallworld. Its core is the method
.as_geojson(_optional out_stream) on the main geometry type mixins.
The GeoJSON Specification is available on geojson.org. It is a 10-minute read and it is easy to implement.
My product is on my github page. Loading the
geojson module adds functionality to the relevant exemplars. Example usage is.
sw_module_manager.load_module(:geojson) $ gis_program_manager.cached_dataset(:gis).collections[:min_road].as_geojson() $
This prints all roads with fields of the default visibility tag as a feature collection. geojson.io is a cool page to verify and view your GeoJSON data. It can also give a good impression of the load on a browser, when many Geometries are rendered.