---

Projections.h

//
// Projections.h
//
// Copyright (c) 2001 Virtual Terrain Project
// Free for all uses, see license.txt for details.
//
// Derived from public-domain USGS software.
//

#ifndef PROJECTIONSH
#define PROJECTIONSH

//
// Enumeration of the Datum types
//
// This list of Datums was originally from the USGS "ProjectionLib" library
// and provides a more concise way to represent a Datum than the string
// values used by OGRSpatialReference.
//
enum DATUM { ADINDAN = 0, ARC1950, ARC1960, AUSTRALIAN_GEODETIC_1966,
             AUSTRALIAN_GEODETIC_1984, CAMP_AREA_ASTRO, CAPE,
             EUROPEAN_DATUM_1950, EUROPEAN_DATUM_1979, GEODETIC_DATUM_1949,
             HONG_KONG_1963, HU_TZU_SHAN, INDIAN, NAD27, NAD83, 
             OLD_HAWAIIAN_MEAN, OMAN, ORDNANCE_SURVEY_1936, PUERTO_RICO, 
             PULKOVO_1942, PROVISIONAL_S_AMERICAN_1956, TOKYO, WGS_72, WGS_84, 
             UNKNOWN_DATUM = -1, NO_DATUM = -2, DEFAULT_DATUM = -3 };

#include "ogr_spatialref.h"


class vtProjection : public OGRSpatialReference
{
public:
    vtProjection();

    // Assignment
    vtProjection &vtProjection::operator=(vtProjection &ref);

    // Equality
    bool operator==(vtProjection &ref);

    bool  IsUTM();
    void  SetUTMZone(int iZone);
    int   GetUTMZone();
    void  SetDatum(DATUM datum);
    DATUM GetDatum();

    void    SetProjectionSimple(int proj_type, int iUTMZone, DATUM eDatum);
    void    SetSpatialReference(OGRSpatialReference *pRef);

    const char *GetProjectionName();
    const char *GetProjectionNameShort();

protected:
    DATUM   m_Datum;
};

struct StatePlaneInfo
{
    char *name;
    int number;
    DATUM datum;
    int usgs_code;
};


// Some class names are just too long!
#define OCT OGRCoordinateTransformation

// Helper functions

const char *datumToString(DATUM d);
StatePlaneInfo *GetStatePlaneTable();
int GetNumStatePlanes();
void CreateSimilarGeographicProjection(vtProjection &source, vtProjection &geo);


#endif  // PROJECTIONSH

---