geojsonio - a new package to do geojson things
geojsonio converts geographic data to GeoJSON and TopoJSON formats - though the focus is mostly on GeoJSON For those not familiar GeoJSON it is a format for encoding a variety of geographic data structures. GeoJSON supports the following geometry types: Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, and GeometryCollection. These geometry types are also found in well known text (WKT), and have equivalents in R’s spatial classes. Read the spec for more detailed information....