Interface HomogeneousDirectPosition

  • All Superinterfaces:
    DirectPosition, Position

    @Draft
    @UML(identifier="DirectPosition",
         specification=ISO_19107)
    public interface HomogeneousDirectPosition
    extends DirectPosition
    A direct position adding another element to the coordinate array which carries a non-zero “weight”, and multiplies all other columns in the coordinate array by that weight. “Homogeneous coordinates” equates, for every w≠0, the coordinate (wx, wy, wz, w) in four-dimensional Euclidean space with the point (x, y, z) in three-dimensional Euclidean space. This mapping is used heavily in projective geometry which aids implementers in creating realistic perspective views of higher dimensional geometry, and will also be used here in the definition of rational splines.
    Since:
    3.1
    Departure from OGC/ISO specification:
    The ISO 19107 draft document defines a single interface, DirectPosition, with a isHomgeneous attribute. In GeoAPI, we keep the historical direct position interface mostly unchanged, defines the new properties in a separated type, and replace the isHomgeneous attribute by a instanceof check.