text: //
  // this is an adapted version of the projects.h file in Gerald Evenden's 
  // USGS PROJ4 projection system
  // Version 6.1 - Kevin Sahr, 5/23/13
  ////////////////////////////////////////////////////////////////////////////////
  
  #ifndef PROJ4_H
  #define PROJ4_H
  
  //#include "projUtil.h"
  /*
  #ifdef __cplusplus
  extern "C" {
  #endif
  */
  
  #ifndef _proj4_constants_
  #define _proj4_constants_
  
  /* some useful constants */
  
  #define projM_PI_180   0.017453292519943295769236907684886L
  #define projM_PI_4     0.785398163397448309615660845819875721L
  #define projM_PI_2     1.570796326794896619231321691639751442L
  #define projM_PI       3.141592653589793238462643383279502884L
  #define projTWOPI      6.28318530717958647692528676655900576L
  
  #endif
  
  
  /* prototype hypot for systems where absent */
  
  extern long double usgs_hypot(long double, long double);
  
  typedef union { long double f; int i; char *s; } PVALUE;
  
  /* procedure prototypes */
  
  long double adjlon(long double);
  long double *pj_enfn(long double);
  long double pj_mlfn(long double, long double, long double, long double *);
  long double pj_inv_mlfn(long double, long double, long double *);
  long double pj_qsfn(long double, long double, long double);
  long double pj_tsfn(long double, long double, long double);
  long double pj_msfn(long double, long double, long double);
  long double pj_phi2(long double, long double);
  long double *pj_authset(long double);
  long double pj_authlat(long double, long double *);
  
  /*
  #ifdef __cplusplus
  }
  #endif
  */
  
  #endif
  
  