Coordinate types

Survey Core understands a large number of ways to express a position.  Not all of these are exposed in the API (some are purely for internal use).  The following is a list of coordinate types, as found in the tsc_CoordType enumeration.

enum tsc_CoordType
{

    tsct_Null             = 0,    // Unknown or irrelevant.     
    tsct_Wgs84            = 1,    // Lat/Long coordinates using the World Geodetic System 1984.
    tsct_Local            = 2,    // As for WGS84, adjusted for the local ellipsoid.
    tsct_Grid             = 4,    // Cartesian coordinates.
    tsct_GridDeltas       = 5,    // The arithmetic difference between two grid coordinates.
    tsct_Ecef             = 6,    // Earth-centered, earth-fixed X-Y-Z (cartesian) coordinates.
    tsct_EcefDeltas       = 8,    // The arithmetic difference between two ECEF coordinates.
    tsct_Unoriented       = 11,   // A corrected polar from the total station, orientation not applied.
    tsct_RawCircle        = 13,   // An uncorrected measurement from a total station.
    tsct_CorrectedCircle  = 14,   // A RawCircle corrected for instrument, atmosphere, and target.
    tsct_Polar            = 15,   // A polar coordinate.
    tsct_StationOffset    = 16,   // A station and offset cartesian deltas with respect to a transformation line.
};

 A Grid coordinate is, for most purposes, the most useful of these and could be considered to be the lowest common denominator.  We could consider there is a "path" from every other coordinate type down to grid, and API methods are provided to perform these conversions.  In most cases the reverse conversions are also available.

The following highly simplified diagram summarises what occurs at each step: