org.orekit.models.earth.tessellation

Interface TileAiming

All Known Implementing Classes:

AlongTrackAiming, ConstantAzimuthAiming, DivertedSingularityAiming

public interface TileAiming

Interface defining the aiming direction of tiles.

Author:

Luc Maisonobe

Method Summary

Modifier and Type	Method and Description
Vector3D	alongTileDirection(Vector3D point, GeodeticPoint gp) Find the along tile direction for tessellation at specified point.
List<GeodeticPoint>	getSingularPoints() Get points at which aiming direction cannot be computed.

Method Detail

getSingularPoints

List<GeodeticPoint> getSingularPoints()

Get points at which aiming direction cannot be computed.

As per Brouwer's hairy ball theorem, any vector field on the 2-sphere has at least one zero. This implies that any implementation of this interface has at least one point where the aiming direction cannot be computed. The most typical example is aiming always towards North pole, for which both poles are singular points.

Returns:

a non-empty (as per hairy ball theorem) list of points where aiming direction is either zero or cannot be computed

Since:

10.0

alongTileDirection

Vector3D alongTileDirection(Vector3D point,
                            GeodeticPoint gp)

Find the along tile direction for tessellation at specified point.

Parameters:

point - point on the ellipsoid (Cartesian coordinates)

gp - point on the ellipsoid (geodetic coordinates)

Returns:

normalized along tile direction