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NASA WorldWind Elevation Type

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  • NASA WorldWind Elevation Type

    Iím trying to determine whether elevation values are relative to the WGS-84 ellipsoid or relative to a particular geoid like EGM-2008. Below are two elevation related function. The first returns elevation at a location in meters. The question is, will that be meters above the WGS-84 ellipsoid (HAE), or will it be meters above a reference geoid or Mean Sea Level (MSL)? The second takes a latitude, longitude and elevation and returns the Cartesian coordinates for the point. Again the question is what type of elevation is expected? Is it meters HAE or MSL?
    1. /**
    2. * Returns the elevation at a specified location.
    3. * @param {Number} latitude The location's latitude in degrees.
    4. * @param {Number} longitude The location's longitude in degrees.
    5. * @returns {Number} The elevation at the specified location, in meters. Returns zero if the location is
    6. * outside the coverage area of this elevation model.
    7. */
    8. ElevationModel.prototype.elevationAtLoca tion = function (latitude, longitude) {
    9. if (!this.coverageSector.containsLocation(l atitude, longitude)) {
    10. return 0; // location is outside the elevation model's coverage
    11. }
    12. return this.pointElevationForLocation(latitude, longitude);
    13. };
    1. /**
    2. * Converts a geographic position to Cartesian coordinates.
    3. *
    4. * @param {Globe} globe The globe this projection is applied to.
    5. * @param {number} latitude The latitude of the position, in degrees.
    6. * @param {number} longitude The longitude of the position, in degrees.
    7. * @param {number} elevation The elevation of the position, in meters.
    8. * @param {Vec3} offset An offset to apply to the Cartesian output. Typically only projections that are
    9. * continuous (see [continuous]{@link GeographicProjection#continuous}) apply to this offset. Others ignore
    10. * it. May be null to indicate no offset is applied.
    11. * @param {Vec3} result A variable in which to store the computed Cartesian point.
    12. *
    13. * @returns {Vec3} The specified result argument containing the computed point.
    14. * @throws {ArgumentError} If the specified globe or result is null or undefined.
    15. */
    16. GeographicProjection.prototype.geographi cToCartesian = function (globe, latitude, longitude, elevation,
    17. offset, result) {
    18. throw new UnsupportedOperationError(
    19. Logger.logMessage(Logger.LEVEL_SEVERE, "GeographicProjection", "geographicToCartesian", "abstractInvocation"));
    20. };