source: branches/fitshead-branch/Utils/position_related.cc

#include <iostream>
#include <sstream>
#include <iomanip>
#include <string>
#include <math.h>
#include <Utils/utils.hh>
#include <param.hh>

using std::setw;
using std::setfill;
using std::setprecision;

string getIAUName(double ra, double dec, FitsHeader head)
{
  /**
   *  string getIAUName(double, double, FitsHeader)
   *   front end to the two getIAUName tasks. It parses the FitsHeader
   *   object and works out the coord type and, if necessary, the
   *   equinox.
   */
  if(head.getWCS()->lngtyp=="RA") 
    return getIAUNameEQ(ra, dec, head.getWCS()->equinox);
  else
    return getIAUNameGAL(ra, dec);
}

string getIAUNameEQ(double ra, double dec, float equinox)
{
  /**
   * string getIAUNameEQ(double, double, float)
   *  both ra and dec are assumed to be in degrees.
   *  returns name of the form J1234-4321 for equinox = 2000, 
   *   and B1234-4321 otherwise
   */

  double raHrs = ra / 15.;
  int h = int(raHrs);
  int m = (int)(fmod(raHrs,1.)*60.);
  std::stringstream ss(std::stringstream::out);
  ss.setf(std::ios::showpoint);
  ss.setf(std::ios::fixed);
  if(equinox==2000.) ss << "J"; 
  else ss << "B";
  ss<<setw(2)<<setfill('0')<<h;
  ss<<setw(2)<<setfill('0')<<m;
  int sign = int( dec / fabs(dec) );
  double d = dec / sign;
  h = int(d);
  m = (int)(fmod(d,1.)*60.);
  if(sign==1) ss<<"+"; else ss<<"-";
  ss<<setw(2)<<setfill('0')<<h;
  ss.unsetf(std::ios::showpos);
  ss<<setw(2)<<setfill('0')<<m;
  return ss.str();
}

string getIAUNameGAL(double lon, double lat)
{
  /**
   * string getIAUNameGAL(double, double)
   *  both ra and dec are assumed to be in degrees.
   *  returns name of the form G321.12+01.23
   */

  std::stringstream ss(std::stringstream::out);
  ss.setf(std::ios::showpoint);
  ss.setf(std::ios::fixed);
  ss<<"G";
  ss<<setw(6)<<setfill('0')<<setprecision(2)<<lon;
  ss.setf(std::ios::showpos);
  ss.setf(std::ios::internal);
  ss<<setw(6)<<setfill('0')<<setprecision(2)<<lat;
  ss.unsetf(std::ios::internal);
  ss.unsetf(std::ios::showpos);
  ss.unsetf(std::ios::showpoint);
  ss.unsetf(std::ios::fixed);
  return ss.str();
}

string decToDMS(const double dec, const string type)
{
  /** 
   *  string decToDMS(double, string)
   *   converts a decimal angle (in degrees) to a format reflecting the axis type:
   *       RA   (right ascension)    --> hh:mm:ss.ss, with dec made modulo 360. (or 24hrs)
   *       DEC  (declination)        --> sdd:mm:ss.ss  (with sign, either + or -)
   *       GLON (galactic longitude) --> ddd:mm:ss.ss, with dec made modulo 360.
   *       GLAT (galactic latitude)  --> sdd:mm:ss.ss  (with sign, either + or -)
   *    Any other type defaults to RA, and prints warning.
   */

  double dec_abs,sec;
  int deg,min;
  const double onemin=1./60.;
  double thisDec = dec;
  string sign="";
  int degSize = 2; // number of figures in the degrees part of the output.

  if((type=="RA")||(type=="GLON")){
    if(type=="GLON")  degSize = 3; // three figures in degrees when doing longitude.
    // Make these modulo 360.;
    while (thisDec < 0.) { thisDec += 360.; }
    while (thisDec >= 360.) { thisDec -= 360.; }
    if(type=="RA") thisDec /= 15.;  // Convert to hours.
  }
  else if((type=="DEC")||(type=="GLAT")){
    if(thisDec<0.) sign = "-";
    else sign = "+";
  }
  else { // UNKNOWN TYPE -- DEFAULT TO RA.
    std::cerr << "WARNING <decToDMS> : Unknown axis type (" << type << "). Defaulting to using RA\n";
    while (thisDec < 0.) { thisDec += 360.; }
    while (thisDec >= 360.) { thisDec -= 360.; }
    thisDec /= 15.;
  }
  
  dec_abs = fabs(thisDec);
  deg = int(dec_abs);//floor(d)
  min = (int)(fmod(dec_abs,1.)*60.);
  sec = fmod(dec_abs,onemin)*3600.;
  if(fabs(sec-60.)<1.e-10){ /* to prevent rounding errors stuffing things up*/
    sec=0.;
    min++;
  }
  std::stringstream ss(std::stringstream::out);
  ss.setf(std::ios::showpoint);
  ss.setf(std::ios::fixed);
  ss << sign;
  ss << setw(degSize)<<setfill('0')<<deg<<":";
  ss<<setw(2)<<setfill('0')<<min<<":";
  ss<<setw(5)<<setprecision(2)<<sec;
  return ss.str();
}


double dmsToDec(string dms)
{
  /** 
   *  double dmsToDec(string)
   *   Converts a string in the format +12:23:34.45 to a decimal angle in degrees.
   *   Assumes the angle given is in degrees, so if passing RA as the argument,
   *   need to multiply by 15 to get the result in degrees rather than hours.
   *   The sign of the angle is preserved, if present.
   */


  bool isNeg = false;
  if(dms[0]=='-') isNeg = true;

  std::stringstream ss;
  ss.str(dms);
  string deg,min,sec;
  getline(ss,deg,':');
  getline(ss,min,':');
  getline(ss,sec);
  char *end;
  double d = strtod(deg.c_str(),&end);
  double m = strtod(min.c_str(),&end);
  double s = strtod(sec.c_str(),&end);  

  double dec = fabs(d) + m/60. + s/3600.;
  if(isNeg) dec = dec * -1.;

  return dec;

}
 
double angularSeparation(double &ra1, double &dec1, double &ra2, double &dec2)
{
  /**
   * double angularSeparation(double &,double &,double &,double &);
   *  Enter ra & dec for two positions.
   *    (all positions in degrees)
   *  Returns the angular separation in degrees.
   */

  double angsep = cos((ra1-ra2)*M_PI/180.)*cos(dec1*M_PI/180.)*cos(dec2*M_PI/180.) 
    + sin(dec1*M_PI/180.)*sin(dec2*M_PI/180.);
  angsep = acos(angsep)*180./M_PI;

  return angsep;

}