For type "LineString", the "coordinates" member must be an array of two or more positions. A LinearRing is closed LineString with 4 or more positions. The first and last positions are equivalent (they represent equivalent points). Though a LinearRing is not explicitly represented as a GeoJSON geometry type, it is referred to in the Polygon geometry type definition.
See also
Other geo types:
Feature
,
FeatureCollection
,
GeometryCollection
,
MultiLineString
,
MultiPoint
,
MultiPolygon
,
Point
,
Polygon
,
geojson-types