Added GHorizDir class to store alt/az coordinates

Karl Kosack
1 parent 7956c168
Showing 4 changed files with 594 additions and 0 deletions
include/GHorizDir.hpp
include/Makefile.am
src/sky/GHorizDir.cpp
src/sky/Makefile.am
+/***************************************************************************
+ *                  GHorizDir.hpp - Horizontal direction class                   *
+ * ----------------------------------------------------------------------- *
+ *  copyright (C) 2008-2013 by Juergen Knoedlseder                         *
+ * ----------------------------------------------------------------------- *
+ *                                                                         *
+ *  This program is free software: you can redistribute it and/or modify   *
+ *  it under the terms of the GNU General Public License as published by   *
+ *  the Free Software Foundation, either version 3 of the License, or      *
+ *  (at your option) any later version.                                    *
+ *                                                                         *
+ *  This program is distributed in the hope that it will be useful,        *
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of         *
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          *
+ *  GNU General Public License for more details.                           *
+ *                                                                         *
+ *  You should have received a copy of the GNU General Public License      *
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.  *
+ *                                                                         *
+ ***************************************************************************/
+/**
+ * @file GHorizDir.hpp
+ * @brief Horizontal direction class interface definition
+ * @author K. Kosack
+ */
+
+#ifndef GSKYDIR_HPP
+#define GSKYDIR_HPP
+
+/* __ Includes ___________________________________________________________ */
+#include <string>
+#include "GBase.hpp"
+#include "GVector.hpp"
+
+/* __ Compile options ____________________________________________________ */
+#define G_SINCOS_CACHE
+
+
+/***********************************************************************//**
+ * @class GHorizDir
+ *
+ * @brief Horizontal (Alt/Az) direction class
+ *
+ * This class is essentially a copy of GSkyDir and implements a
+ * spherical coordinate on the sky, in horizontal coordinates as seen
+ * from Earth. 
+ *
+ * @note since this class shares much functionality with GSkyDir, a
+ * common base-class should probably be created in the future to avoid
+ * duplication of code.
+ ***************************************************************************/
+class GHorizDir : public GBase {
+
+    // Operator friends
+    friend bool operator==(const GHorizDir &a, const GHorizDir &b);
+    friend bool operator!=(const GHorizDir &a, const GHorizDir &b);
+
+public:
+    // Constructors and destructors
+    GHorizDir(void);
+    GHorizDir(const GHorizDir& dir);
+    virtual ~GHorizDir(void);
+
+    // Operators
+    GHorizDir& operator= (const GHorizDir& dir);
+
+    // Methods
+    void          clear(void);
+    GHorizDir*    clone(void) const;
+    void          altaz(const double& alt, const double& az);
+    void          altaz_deg(const double& alt, const double& az);
+    void          celvector(const GVector& vector);
+    void          rotate_deg(const double& phi, const double& theta);
+    const double& alt(void) const;
+    const double& az(void) const;
+    double        zenith() const;
+    double        zenith_deg() const;
+    double        alt_deg(void) const;
+    double        az_deg(void) const;
+    GVector       celvector(void) const;
+    double        dist(const GHorizDir& dir) const;
+    double        dist_deg(const GHorizDir& dir) const;
+    std::string   print(const GChatter& chatter = NORMAL) const;
+  
+
+private:
+    // Private methods
+    void init_members(void);
+    void copy_members(const GHorizDir& dir);
+    void free_members(void);
+
+    // Private members
+    double m_alt;         //!< altitude in radians
+    double m_az;        //!< azimuth in radians
+
+    // Sincos cache
+    // #if defined(G_SINCOS_CACHE)
+    // mutable bool   m_has_lb_cache;
+    // mutable bool   m_has_radec_cache;
+    // mutable double m_sin_b;
+    // mutable double m_cos_b;
+    // mutable double m_sin_dec;
+    // mutable double m_cos_dec;
+    // #endif
+};
+
+
+/***********************************************************************//**
+ * @brief Return zenith angle in radians
+ *
+ * @return zenith angle in radians
+ ***************************************************************************/
+inline
+double GHorizDir::zenith() 
+{
+    return gammalib::pihalf - m_alt;
+};
+
+/***********************************************************************//**
+ * @brief Return zenith angle in radians
+ *
+ * @return zenith angle in radians
+ ***************************************************************************/
+inline
+double GHorizDir::zenith_deg() 
+{
+    return zenith() * gammalib::rad2deg;
+};
+
+
+#endif /* GHORIZDIR_HPP */
@@ -77,6 +77,7 @@ pkginclude_HEADERS = GammaLib.hpp \
                      GTestSuites.hpp \
                      GTestCase.hpp \
                      GSkyDir.hpp \
+                     GHorizDir.hpp \
                      GSkyPixel.hpp \
                      GSkymap.hpp \
                      GSkyRegion.hpp \
+/***************************************************************************
+ *                  GHorizDir.cpp - Horizontal direction class                   *
+ * ----------------------------------------------------------------------- *
+ *  copyright (C) 2008-2013 by Juergen Knoedlseder                         *
+ * ----------------------------------------------------------------------- *
+ *                                                                         *
+ *  This program is free software: you can redistribute it and/or modify   *
+ *  it under the terms of the GNU General Public License as published by   *
+ *  the Free Software Foundation, either version 3 of the License, or      *
+ *  (at your option) any later version.                                    *
+ *                                                                         *
+ *  This program is distributed in the hope that it will be useful,        *
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of         *
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          *
+ *  GNU General Public License for more details.                           *
+ *                                                                         *
+ *  You should have received a copy of the GNU General Public License      *
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.  *
+ *                                                                         *
+ ***************************************************************************/
+/**
+ * @file GHorizDir.cpp
+ * @brief Horiz direction class implementation
+ * @author K. Kosack
+ */
+
+/* __ Includes ___________________________________________________________ */
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <cmath>
+#include "GException.hpp"
+#include "GTools.hpp"
+#include "GMath.hpp"
+#include "GHorizDir.hpp"
+#include "GMatrix.hpp"
+#include "GVector.hpp"
+
+/* __ Method name definitions ____________________________________________ */
+
+/* __ Macros _____________________________________________________________ */
+
+/* __ Coding definitions _________________________________________________ */
+
+/* __ Debug definitions __________________________________________________ */
+
+/* __ Prototypes _________________________________________________________ */
+
+/*==========================================================================
+ =                                                                         =
+ =                          Constructors/destructors                       =
+ =                                                                         =
+ ==========================================================================*/
+
+/***********************************************************************//**
+ * @brief Constructor
+ ***************************************************************************/
+GHorizDir::GHorizDir(void)
+{
+    // Initialise members
+    init_members();
+
+    // Return
+    return;
+}
+
+
+/***********************************************************************//**
+ * @brief Copy constructor
+ *
+ * @param[in] dir Horiz direction.
+ ***************************************************************************/
+GHorizDir::GHorizDir(const GHorizDir& dir)
+{
+    // Initialise members
+    init_members();
+
+    // Copy members
+    copy_members(dir);
+
+    // Return
+    return;
+}
+
+
+/***********************************************************************//**
+ * @brief Destructor
+ ***************************************************************************/
+GHorizDir::~GHorizDir(void)
+{
+    // Free members
+    free_members();
+
+    // Return
+    return;
+}
+
+
+/*==========================================================================
+ =                                                                         =
+ =                                Operators                                =
+ =                                                                         =
+ ==========================================================================*/
+
+/***********************************************************************//**
+ * @brief Assignment operator
+ *
+ * @param[in] dir Horiz direction.
+ * @return Horiz direction.
+ ***************************************************************************/
+GHorizDir& GHorizDir::operator= (const GHorizDir& dir)
+{
+    // Execute only if object is not identical
+    if (this != &dir) {
+
+        // Free members
+        free_members();
+
+        // Initialise members
+        init_members();
+
+        // Copy members
+        copy_members(dir);
+
+    } // endif: object was not identical
+
+    // Return this object
+    return *this;
+}
+
+
+/*==========================================================================
+ =                                                                         =
+ =                              Public methods                             =
+ =                                                                         =
+ ==========================================================================*/
+
+/***********************************************************************//**
+ * @brief Clear sky direction
+ ***************************************************************************/
+void GHorizDir::clear(void)
+{
+    // Free members
+    free_members();
+
+    // Initialise members
+    init_members();
+
+    // Return
+    return;
+}
+
+
+/***********************************************************************//**
+ * @brief Clone sky direction
+ *
+ * @return Pointer to deep copy of sky direction.
+ ***************************************************************************/
+GHorizDir* GHorizDir::clone(void) const
+{
+    // Clone sky direction
+    return new GHorizDir(*this);
+}
+
+
+/***********************************************************************//**
+ * @brief Set equatorial sky direction (radians)
+ *
+ * @param[in] ra Right Ascension in radians.
+ * @param[in] dec Declination in radians.
+ *
+ * Sets Right Ascension and Declination in radians.
+ ***************************************************************************/
+void GHorizDir::altaz(const double& alt, const double& az)
+{
+
+    // Set direction
+    m_alt  = alt;
+    m_az = az;
+
+    // Return
+    return;
+}
+
+
+/***********************************************************************//**
+ * @brief Set equatorial sky direction (degrees)
+ *
+ * @param[in] ra Right Ascension in degrees.
+ * @param[in] dec Declination in degrees.
+ *
+ * Sets Right Ascension and Declination in degrees.
+ ***************************************************************************/
+void GHorizDir::altaz_deg(const double& alt, const double& az)
+{
+
+    // Set direction
+    m_ra  = alt  * gammalib::deg2rad;
+    m_dec = az * gammalib::deg2rad;
+
+    // Return
+    return;
+}
+
+
+/***********************************************************************//**
+ * @brief Set sky direction from 3D vector in horizontal coordinates
+ *
+ * @param[in] vector 3D vector.
+ *
+ * Convert a 3-dimensional vector in celestial coordinates into a sky
+ * direction. The transformation is given by
+ *
+ * \f[
+ *    \alpha = \arctan \left( \frac{x_1}{x_0} \right)
+ * \f]
+ *
+ * \f[
+ *    \delta = \arcsin x_2
+ * \f]
+ ***************************************************************************/
+void GHorizDir::celvector(const GVector& vector)
+{
+
+
+    // Convert vector into sky position
+    m_alt = std::asin(vector[2]);
+    m_az  = std::atan2(vector[1], vector[0]);
+
+    // Return
+    return;
+}
+
+
+/***********************************************************************//**
+ * @brief Rotate sky direction by zenith and azimuth angle
+ *
+ * @param[in] phi Azimuth angle (deg).
+ * @param[in] theta Zenith angle (deg).
+ *
+ * Rotate sky direction by a zenith and azimuth angle given in the system
+ * of the sky direction and aligned in celestial coordinates. 
+ * The azimuth angle is counted counter clockwise from celestial north
+ * (this is identical to the astronomical definition of a position angle).
+ ***************************************************************************/
+void GHorizDir::rotate_deg(const double& phi, const double& theta)
+{
+
+    // Allocate Euler and rotation matrices
+    GMatrix ry;
+    GMatrix rz;
+
+    // Set up rotation matrix to rotate from native coordinates to
+    // celestial coordinates
+    ry.eulery(m_alt * gammalib::rad2deg - 90.0);
+    rz.eulerz(-m_az * gammalib::rad2deg);
+    GMatrix rot = (ry * rz).transpose();
+
+    // Set up native coordinate vector
+    double phi_rad   = phi   * gammalib::deg2rad;
+    double theta_rad = theta * gammalib::deg2rad;
+    double cos_phi   = std::cos(phi_rad);
+    double sin_phi   = std::sin(phi_rad);
+    double cos_theta = std::cos(theta_rad);
+    double sin_theta = std::sin(theta_rad);
+    GVector native(-cos_phi*sin_theta, sin_phi*sin_theta, cos_theta);
+
+    // Rotate vector into celestial coordinates
+    GVector dir = rot * native;
+
+    // Convert vector into sky position
+    celvector(dir);
+
+    // Return
+    return;
+}
+
+
+/***********************************************************************//**
+ * @brief Return sky direction as 3D vector in celestial coordinates
+ *
+ * @return Horiz direction as 3D vector in celestial coordinates.
+ ***************************************************************************/
+GVector GHorizDir::celvector(void) const
+{
+    // Compute 3D vector
+    double  cosaz  = std::cos(m_az);
+    double  sinaz  = std::sin(m_az);
+    double  cosalt = std::cos(m_alt);
+    double  sinalt = std::sin(m_alt);
+    GVector vector(cosdec*cosaz, cosdec*sinaz, sinalt);
+
+    // Return vector
+    return vector;
+}
+
+
+/***********************************************************************//**
+ * @brief Compute angular distance between sky directions in radians
+ *
+ * @param[in] dir Horiz direction to which distance is to be computed.
+ * @return Angular distance in radians.
+ *
+ * Computes the angular distance between two sky directions in radians.
+ ***************************************************************************/
+double GHorizDir::dist(const GHorizDir& dir) const
+{
+    // Initialise cosine of distance
+    double cosdis;
+
+    // Compute dependent on coordinate system availability. This speeds
+    // up things by avoiding unnecessary coordinate transformations.
+
+    cosdis = sin(m_alt) * sin(dir.alt()) +
+      cos(m_alt) * cos(dir.alt()) *
+      std::cos(dir.az() - m_az);
+    
+    // Compute distance (use argument save GTools function)
+    double dist = gammalib::acos(cosdis);
+
+    // Return distance
+    return dist;
+}
+
+
+/***********************************************************************//**
+ * @brief Compute angular distance between sky directions in degrees
+ *
+ * @param[in] dir Horiz direction to which distance is to be computed.
+ * @return Angular distance in degrees.
+ *
+ * Computes the angular distance between two sky directions in degrees.
+ ***************************************************************************/
+double GHorizDir::dist_deg(const GHorizDir& dir) const
+{
+    // Return distance in degrees
+    return (dist(dir) * gammalib::rad2deg);
+}
+
+
+
+/***********************************************************************//**
+ * @brief Print horizontal direction information
+ *
+ * @param[in] chatter Chattiness (defaults to NORMAL).
+ * @return String containing sky direction information.
+ ***************************************************************************/
+std::string GHorizDir::print(const GChatter& chatter) const
+{
+    // Initialise result string
+    std::string result;
+
+    // Continue only if chatter is not silent
+    if (chatter != SILENT) {
+
+      // Put coordinates in string
+      result = "(Az,Alt)=("+gammalib::str(m_az*gammalib::rad2deg) + "," +
+        gammalib::str(m_alt*gammalib::rad2deg)+")";
+      
+    } // endif: chatter was not silent
+
+    // Return result
+    return result;
+}
+
+
+/*==========================================================================
+ =                                                                         =
+ =                             Private methods                             =
+ =                                                                         =
+ ==========================================================================*/
+
+/***********************************************************************//**
+ * @brief Initialise class members
+ ***************************************************************************/
+void GHorizDir::init_members(void)
+{
+    // Initialise members
+    m_az        = 0.0;
+    m_alt       = 0.0;
+
+    // Return
+    return;
+}
+
+
+/***********************************************************************//**
+ * @brief Copy class members
+ *
+ * @param[in] dir Horiz direction.
+ ***************************************************************************/
+void GHorizDir::copy_members(const GHorizDir& dir)
+{
+    m_az        = dir.m_az;
+    m_alt       = dir.m_alt;
+
+    // Return
+    return;
+}
+
+
+/***********************************************************************//**
+ * @brief Delete class members
+ ***************************************************************************/
+void GHorizDir::free_members(void)
+{
+    // Return
+    return;
+}
+
+
+/*==========================================================================
+ =                                                                         =
+ =                                 Friends                                 =
+ =                                                                         =
+ ==========================================================================*/
+
+/***********************************************************************
+ * @brief Equality operator
+ *
+ * @param[in] a First horiz direction.
+ * @param[in] b Second horiz direction.
+ *
+ * Compare two horiz directions. If the coordinate is at the pole, the
+ * Azimuth value is irrelevant.
+ *
+ * @todo: really should test for being within some tolerance here
+ *
+ ***************************************************************************/
+bool operator==(const GHorizDir &a, const GHorizDir &b)
+{
+    // Initialise result
+    bool equal = false;
+    
+    // Compute dependent on coordinate system availability. This speeds
+    // up things by avoiding unnecessary coordinate transformations.
+    
+    if (std::abs(std::abs(a.m_alt) - 90.0) < 1e-10) {
+        equal = (a.m_alt == b.m_alt);
+    }
+    else {
+        equal = (a.m_alt == b.m_alt && a.m_az == b.m_az);
+    }
+    
+    // Return equality
+    return equal;
+}
+
+
+/***********************************************************************//**
+ * @brief Non equality operator
+ *
+ * @param[in] a First sky direction.
+ * @param[in] b Second sky direction.
+ ***************************************************************************/
+bool operator!=(const GHorizDir &a, const GHorizDir &b)
+{
+    // Return non equality
+    return (!(a==b));
+}
+
@@ -7,6 +7,7 @@ INCLUDES = -I$(top_srcdir)/include \
 # Define sources for this directory
 sources = GSkyDir.cpp \
+	  GHorizDir.cpp \
           GSkyPixel.cpp \
           GSkymap.cpp \
           GSkyRegions.cpp \