Coordinate value accessors on position classes

[navispatial]

The definition for generic coordinate value accessor on BasePosition:

  /// A coordinate value by the coordinate axis index [i].
  /// 
  /// Returns zero when a coordinate axis is not available.
  /// 
  /// For projected or cartesian coordinates, the coordinate ordering is: 
  /// (x, y), (x, y, m), (x, y, z) or (x, y, z, m).
  ///
  /// For geographic coordinates, the coordinate ordering is: 
  /// (lon, lat), (lon, lat, m), (lon, lat, elev) or (lon, lat, elev, m).
  num operator [](int i);

  /// Coordinate values of this position as an iterable of 2, 3 or 4 items.
  /// 
  /// For projected or cartesian coordinates, the coordinate ordering is: 
  /// (x, y), (x, y, m), (x, y, z) or (x, y, z, m).
  ///
  /// For geographic coordinates, the coordinate ordering is: 
  /// (lon, lat), (lon, lat, m), (lon, lat, elev) or (lon, lat, elev, m).
  Iterable<num> get values;

Implemented by Position and GeoPosition.

[navispatial]

Implemented in pre-release 0.1.0-a.1 of beta 0.1.0 of geobase.