API_GISCoordinateSystem

Describes a geographical or projected map coordinate system.

    typedef struct {
        GISCoordinateSystemType       type;
        API_GISEPSGData               mainCRS;
        API_GISEPSGData               datum;
        API_GISEPSGData               primeMeridian;
        API_GISEPSGData               ellipsoid;
        API_GISEPSGData               sourceCRS;
        API_GISEPSGData               projection;
        API_GISEPSGData               coordOpM;
        API_GISMapProjectionParam     **mapProjParams;
        GISLinearUnit                 uvUnit;
        GISLinearUnit                 hUnit;
        GISAngularUnit                 angleUnit;
        Int32                         filler_1;
    } API_GISCoordinateSystem;

Members

type: CST_Unknown, CST_Geographic (longitude and latitude) or CST_Projected (map projections using linear units)
mainCRS: Coordinate Reference System (CRS), it can be geographical or projected
datum: Datum of CRS
primeMeridian: Prime Meridian of CRS
ellipsoid: Ellipsoid of CRS
sourceCRS: Source geographical CRS, if type is projected
projection: Map projection, if type is projected
coordOpM: Coordinate operation method
mapProjParams: Handle of the variable numbered projection parameters
uvUnit: Units of valus in map plane
hUnit: Height unit
angleUnit: Angle unit

Remarks

This structure can describe two types of coordinate systems: geographical and projected. Geographical coordinate systems are spherical coordinate system a position is described by two angles: longitude and latitude. These angles are measured from the Equator and the Prime Meridian of the Earth.
Projected coordinate systems are built up by a projection; Earth surface is projected to a map plan. A position is described by two linear distances from a datum on map plan.

This structure can describe all the coordinate systems that can be found at the home page of the European Petroleum Survey Group (http://www.epsg.org). It stores EPSG references of coordinate system parameters, and also has units and database type selectors enabling simple calculatons and conversions between geodetic parameters and SI units.

Requirements

Version: API 6.1 or later

Header: APIdefs_Database.h

Members

Remarks

Requirements

See Also