Class GeoJsonCodec

A GeoJsonCodec is responsible for 2 things:

• encode a Feature instance to a JavaScript object that adheres to the GeoJSON specification

• decode a GeoJSON JavaScript object to a Feature.

  Since a 1-on-1 mapping from a GeoJSON geometry to a LuciadRIA shape does not exist, the codec decodes GeoJSON geometries to shapes as follows:

  • Points, LineStrings, Polygons GeoJSON geometries are mapped to LuciadRIA Point, Polyline and Polygon or ComplexPolygon instances respectively. Note that a GeoJSON Polygon is decoded to a Polygon, if it only consists of a single ring.
  • MultiPoints, MultiLineStrings, MultiPolygons are all mapped to a ShapeList, containing only LuciadRIA Point, Polyline and ComplexPolygon or Polygon instances.
  • GeometryCollections are mapped to ShapeList instances.

  The codec encodes the shape of the feature to GeoJSON geometries as follows:

  • Point and Polyline instances are mapped to GeoJSON Points and LineStrings respectively.
  • Polygon and ComplexPolygon instances are all mapped to GeoJSON Polygons.
  • ShapeList that consist solely of Point or Polyline instances are mapped to MultiPoint and MultiLineString geometries respectively.
  • ShapeList that consist of a mix of Polygon and ComplexPolygon instances are mapped to GeoJSON MultiPolygons.
  • ShapeList that contain an arbitrary mix of shapes are mapped to GeoJSON GeometryCollections.

  GeoJSON does not support any other shapes than Point, Linestring, Polygon, MultiPoint, MultiLinestring, MultiPolygon, GeometryCollection. As such, it cannot support all shapes of LuciadRIA. For example, a Circle cannot be represented directly as a circle in GeoJSON. To deal with such shapes, a custom codec is required. The CreateEdit sample shows how you can create a custom codec for such shapes.