gov.nasa.worldwind.globe

Interface Terrain

All Known Implementing Classes:

BasicTerrain

public interface Terrain

Surface of a planet or celestial object.

Models the geometric surface defined by an ellipsoidal globe and its associated elevations. Terrain uses the Cartesian coordinate system specified by a GeographicProjection and is capable of representing both a 3D ellipsoid and a 2D map projection, though not simultaneously.

Caching Terrain Queries

Terrain implementations typically model a subset of the globe's surface at varying resolution. In this case results from the methods intersect and surfacePoint cannot be cached. Either method may fail to compute a result when the terrain surface has no geometry in the region queried, and even if computation is successful the result is based on an unknown resolution. However, if the terrain implementation is known to model a pre-determined resolution and region of interest results from the methods intersect and surfacePoint may be cached.

See Also:

GeographicProjection

Method Summary

Modifier and Type	Method and Description
Sector	getSector() Indicates the geographic rectangular region that contains this terrain.
boolean	intersect(Line line, Vec3 result) Computes the first intersection of this terrain with a specified line in Cartesian coordinates.
boolean	surfacePoint(double latitude, double longitude, Vec3 result) Computes the Cartesian coordinates of a geographic location on the terrain surface.

Method Detail

getSector

Sector getSector()

Indicates the geographic rectangular region that contains this terrain. The returned sector may contain geographic areas where the terrain is nonexistent.

Returns:

the terrain's bounding sector

intersect

boolean intersect(Line line,
                  Vec3 result)

Computes the first intersection of this terrain with a specified line in Cartesian coordinates. The line is interpreted as a ray; intersection points behind the line's origin are ignored. If the line does not intersect the geometric surface modeled by this terrain, this returns false and does not modify the result argument.

Parameters:

line - the line to intersect with this terrain

result - a pre-allocated Vec3 in which to return the intersection point

Returns:

true if the ray intersects this terrain, otherwise false

Throws:

java.lang.IllegalArgumentException - if either argument is null

surfacePoint

boolean surfacePoint(double latitude,
                     double longitude,
                     Vec3 result)

Computes the Cartesian coordinates of a geographic location on the terrain surface. If the latitude and longitude are outside the geometric surface modeled by this terrain, this returns false and does not modify the result argument.

Parameters:

latitude - the location's latitude in degrees

longitude - the location's longitude in degrees

result - a pre-allocated Vec3 in which to store the computed X, Y and Z Cartesian coordinates

Returns:

true if the geographic location is on the terrain surface, otherwise false

Throws:

java.lang.IllegalArgumentException - if the result is null