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GWcsMER.cpp
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1 /***************************************************************************
2  * GWcsMER.cpp - Mercator's (MER) projection class *
3  * ----------------------------------------------------------------------- *
4  * copyright (C) 2012-2021 by Juergen Knoedlseder *
5  * ----------------------------------------------------------------------- *
6  * *
7  * This program is free software: you can redistribute it and/or modify *
8  * it under the terms of the GNU General Public License as published by *
9  * the Free Software Foundation, either version 3 of the License, or *
10  * (at your option) any later version. *
11  * *
12  * This program is distributed in the hope that it will be useful, *
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of *
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
15  * GNU General Public License for more details. *
16  * *
17  * You should have received a copy of the GNU General Public License *
18  * along with this program. If not, see <http://www.gnu.org/licenses/>. *
19  * *
20  ***************************************************************************/
21 /**
22  * @file GWcsMER.cpp
23  * @brief Mercator's (MER) projection class implementation
24  * @author Juergen Knoedlseder
25  */
26 
27 /* __ Includes ___________________________________________________________ */
28 #ifdef HAVE_CONFIG_H
29 #include <config.h>
30 #endif
31 #include "GException.hpp"
32 #include "GMath.hpp"
33 #include "GWcsMER.hpp"
34 #include "GWcsRegistry.hpp"
35 
36 /* __ Method name definitions ____________________________________________ */
37 #define G_PRJ_X2S "GWcsMER::prj_x2s(int, int, int, int, double*, double*,"\
38  " double*, double*, int*)"
39 
40 /* __ Macros _____________________________________________________________ */
41 
42 /* __ Coding definitions _________________________________________________ */
43 
44 /* __ Debug definitions __________________________________________________ */
45 
46 /* __ Local prototypes ___________________________________________________ */
47 
48 /* __ Constants __________________________________________________________ */
49 
50 /* __ Globals ____________________________________________________________ */
52 const GWcsRegistry g_wcs_mer_registry(&g_wcs_mer_seed);
53 
54 
55 /*==========================================================================
56  = =
57  = Constructors/destructors =
58  = =
59  ==========================================================================*/
60 
61 /***********************************************************************//**
62  * @brief Void constructor
63  ***************************************************************************/
65 {
66  // Initialise class members
67  init_members();
68 
69  // Return
70  return;
71 }
72 
73 
74 /***********************************************************************//**
75  * @brief Projection constructor
76  *
77  * @param[in] coords Coordinate system.
78  * @param[in] crval1 X value of reference pixel.
79  * @param[in] crval2 Y value of reference pixel.
80  * @param[in] crpix1 X index of reference pixel (starting from 1).
81  * @param[in] crpix2 Y index of reference pixel (starting from 1).
82  * @param[in] cdelt1 Increment in x direction at reference pixel [deg].
83  * @param[in] cdelt2 Increment in y direction at reference pixel [deg].
84  ***************************************************************************/
85 GWcsMER::GWcsMER(const std::string& coords,
86  const double& crval1, const double& crval2,
87  const double& crpix1, const double& crpix2,
88  const double& cdelt1, const double& cdelt2) :
89  GWcs(coords, crval1, crval2, crpix1, crpix2, cdelt1, cdelt2)
90 
91 {
92  // Initialise class members
93  init_members();
94 
95  // Setup WCS derived parameters
96  wcs_set();
97 
98  // Return
99  return;
100 }
101 
102 
103 /***********************************************************************//**
104  * @brief Copy constructor
105  *
106  * @param[in] wcs World Coordinate System.
107  ***************************************************************************/
108 GWcsMER::GWcsMER(const GWcsMER& wcs) : GWcs(wcs)
109 {
110  // Initialise class members for clean destruction
111  init_members();
112 
113  // Copy members
114  copy_members(wcs);
115 
116  // Return
117  return;
118 }
119 
120 
121 /***********************************************************************//**
122  * @brief Destructor
123  ***************************************************************************/
125 {
126  // Free members
127  free_members();
128 
129  // Return
130  return;
131 }
132 
133 
134 /*==========================================================================
135  = =
136  = Operators =
137  = =
138  ==========================================================================*/
139 
140 /***********************************************************************//**
141  * @brief Assignment operator
142  *
143  * @param[in] wcs World Coordinate System.
144  * @return World Coordinate System.
145  ***************************************************************************/
147 {
148  // Execute only if object is not identical
149  if (this != &wcs) {
150 
151  // Copy base class members
152  this->GWcs::operator=(wcs);
153 
154  // Free members
155  free_members();
156 
157  // Initialise private members for clean destruction
158  init_members();
159 
160  // Copy members
161  copy_members(wcs);
162 
163  } // endif: object was not identical
164 
165  // Return this object
166  return *this;
167 }
168 
169 
170 /*==========================================================================
171  = =
172  = Public methods =
173  = =
174  ==========================================================================*/
175 
176 /***********************************************************************//**
177  * @brief Clear Mercator's projection
178  *
179  * This method properly resets the object to an initial state.
180  ***************************************************************************/
181 void GWcsMER::clear(void)
182 {
183  // Free class members (base and derived classes, derived class first)
184  free_members();
185  this->GWcs::free_members();
187 
188  // Initialise members
190  this->GWcs::init_members();
191  init_members();
192 
193  // Return
194  return;
195 }
196 
197 
198 /***********************************************************************//**
199  * @brief Clone Mercator's projection
200  *
201  * @return Pointer to deep copy of Mercator's projection.
202  ***************************************************************************/
204 {
205  return new GWcsMER(*this);
206 }
207 
208 
209 /***********************************************************************//**
210  * @brief Print WCS information
211  *
212  * @param[in] chatter Chattiness (defaults to NORMAL).
213  * @return String containing Mercator's projection information.
214  ***************************************************************************/
215 std::string GWcsMER::print(const GChatter& chatter) const
216 {
217  // Initialise result string
218  std::string result;
219 
220  // Continue only if chatter is not silent
221  if (chatter != SILENT) {
222 
223  // Append header
224  result.append("=== GWcsMER ===");
225 
226  // Append information
227  result.append(wcs_print(chatter));
228 
229  } // endif: chatter was not silent
230 
231  // Return result
232  return result;
233 }
234 
235 
236 /*==========================================================================
237  = =
238  = Private methods =
239  = =
240  ==========================================================================*/
241 
242 /***********************************************************************//**
243  * @brief Initialise class members
244  ***************************************************************************/
246 {
247  // Return
248  return;
249 }
250 
251 
252 /***********************************************************************//**
253  * @brief Copy class members
254  *
255  * @param[in] wcs World Coordinate System.
256  ***************************************************************************/
258 {
259  // Return
260  return;
261 }
262 
263 
264 /***********************************************************************//**
265  * @brief Delete class members
266  ***************************************************************************/
268 {
269  // Return
270  return;
271 }
272 
273 
274 /***********************************************************************//**
275  * @brief Setup of projection
276  *
277  * This method sets up the projection information. The method has been
278  * adapted from the wcslib function prj.c::merset.
279  *
280  * Given and/or returned:
281  * m_r0 Reset to 180/pi if 0.
282  * m_phi0 Reset to 0.0 if undefined.
283  * m_theta0 Reset to 0.0 if undefined.
284  *
285  * Returned:
286  * m_x0 Fiducial offset in x.
287  * m_y0 Fiducial offset in y.
288  * m_w[0] r0*(pi/180)
289  * m_w[1] (180/pi)/r0
290  ***************************************************************************/
291 void GWcsMER::prj_set(void) const
292 {
293  // Signal that projection has been set (needs to be done before calling
294  // the prj_off() method to avoid an endless loop)
295  m_prjset = true;
296 
297  // Initialise projection parameters
298  m_w.clear();
299 
300  // Precompute
301  if (m_r0 == 0.0) {
303  m_w.push_back(1.0);
304  m_w.push_back(1.0);
305  }
306  else {
307  m_w.push_back(m_r0 * gammalib::deg2rad);
308  m_w.push_back(1.0/m_w[0]);
309  }
310 
311  // Compute fiducial offset
312  prj_off(0.0, 0.0);
313 
314  // Return
315  return;
316 }
317 
318 
319 /***********************************************************************//**
320  * @brief Pixel-to-spherical deprojection
321  *
322  * @param[in] nx X vector length.
323  * @param[in] ny Y vector length (0=no replication).
324  * @param[in] sxy Input vector step.
325  * @param[in] spt Output vector step.
326  * @param[in] x Vector of projected x coordinates.
327  * @param[in] y Vector of projected y coordinates.
328  * @param[out] phi Longitude of the projected point in native spherical
329  * coordinates [deg].
330  * @param[out] theta Latitude of the projected point in native spherical
331  * coordinates [deg].
332  * @param[out] stat Status return value for each vector element (always 0)
333  *
334  * Deproject pixel (x,y) coordinates in the plane of projection to native
335  * spherical coordinates (phi,theta).
336  *
337  * This method has been adapted from the wcslib function prj.c::merx2s().
338  * The interface follows very closely that of wcslib. In contrast to the
339  * wcslib routine, however, the method assumes that the projection has been
340  * setup previously (as this will be done by the constructor).
341  ***************************************************************************/
342 void GWcsMER::prj_x2s(int nx, int ny, int sxy, int spt,
343  const double* x, const double* y,
344  double* phi, double* theta, int* stat) const
345 {
346  // Initialize projection if required
347  if (!m_prjset) {
348  prj_set();
349  }
350 
351  // Set value replication length mx,my
352  int mx;
353  int my;
354  if (ny > 0) {
355  mx = nx;
356  my = ny;
357  }
358  else {
359  mx = 1;
360  my = 1;
361  ny = nx;
362  }
363 
364  // Do x dependence
365  const double* xp = x;
366  int rowoff = 0;
367  int rowlen = nx * spt;
368  for (int ix = 0; ix < nx; ++ix, rowoff += spt, xp += sxy) {
369  double s = m_w[1] * (*xp + m_x0);
370  double* phip = phi + rowoff;
371  for (int iy = 0; iy < my; ++iy, phip += rowlen) {
372  *phip = s;
373  }
374  }
375 
376  // Do y dependence
377  const double* yp = y;
378  double* thetap = theta;
379  int* statp = stat;
380  for (int iy = 0; iy < ny; ++iy, yp += sxy) {
381  double t = 2.0 * gammalib::atand(std::exp((*yp + m_y0)/m_r0)) - 90.0;
382  for (int ix = 0; ix < mx; ++ix, thetap += spt) {
383  *thetap = t;
384  *(statp++) = 0;
385  }
386  }
387 
388  // Do boundary checking
389  int status = prj_bchk(1.0e-13, nx, my, spt, phi, theta, stat);
390 
391  // Check status code
393 
394  // Return
395  return;
396 }
397 
398 
399 /***********************************************************************//**
400  * @brief Generic spherical-to-pixel projection
401  *
402  * @param[in] nphi Longitude vector length.
403  * @param[in] ntheta Latitude vector length (0=no replication).
404  * @param[in] spt Input vector step.
405  * @param[in] sxy Output vector step.
406  * @param[in] phi Longitude vector of the projected point in native spherical
407  * coordinates [deg].
408  * @param[in] theta Latitude vector of the projected point in native spherical
409  * coordinates [deg].
410  * @param[out] x Vector of projected x coordinates.
411  * @param[out] y Vector of projected y coordinates.
412  * @param[out] stat Status return value for each vector element (always 0)
413  *
414  * Project native spherical coordinates (phi,theta) to pixel (x,y)
415  * coordinates in the plane of projection.
416  *
417  * This method has been adapted from the wcslib function prj.c::mers2x().
418  * The interface follows very closely that of wcslib. In contrast to the
419  * wcslib routine, however, the method assumes that the projection has been
420  * setup previously (as this will be done by the constructor).
421  ***************************************************************************/
422 void GWcsMER::prj_s2x(int nphi, int ntheta, int spt, int sxy,
423  const double* phi, const double* theta,
424  double* x, double* y, int* stat) const
425 {
426  // Initialize projection if required
427  if (!m_prjset) {
428  prj_set();
429  }
430 
431  // Set value replication length mphi,mtheta
432  int mphi;
433  int mtheta;
434  if (ntheta > 0) {
435  mphi = nphi;
436  mtheta = ntheta;
437  }
438  else {
439  mphi = 1;
440  mtheta = 1;
441  ntheta = nphi;
442  }
443 
444  // Initialise status code and statistics
445  //int status = 0;
446  int n_invalid = 0;
447 
448  // Do phi dependence
449  const double* phip = phi;
450  int rowoff = 0;
451  int rowlen = nphi * sxy;
452  for (int iphi = 0; iphi < nphi; ++iphi, rowoff += sxy, phip += spt) {
453  double xi = m_w[0] * (*phip) - m_x0;
454  double* xp = x + rowoff;
455  for (int itheta = 0; itheta < mtheta; ++itheta, xp += rowlen) {
456  *xp = xi;
457  }
458  }
459 
460 
461  // Do theta dependence
462  const double* thetap = theta;
463  double* yp = y;
464  int* statp = stat;
465  for (int itheta = 0; itheta < ntheta; ++itheta, thetap += spt) {
466  double eta;
467  int istat = 0;
468  if (*thetap <= -90.0 || *thetap >= 90.0) {
469  eta = 0.0;
470  istat = 1;
471  n_invalid++;
472  }
473  else {
474  eta = m_r0 * std::log(gammalib::tand((*thetap+90.0)/2.0)) - m_y0;
475  }
476  for (int iphi = 0; iphi < mphi; ++iphi, yp += sxy) {
477  *yp = eta;
478  *(statp++) = istat;
479  }
480  }
481 
482  // Return
483  return;
484 }
double tand(const double &angle)
Compute tangens of angle in degrees.
Definition: GMath.cpp:192
void init_members(void)
Initialise class members.
Definition: GWcs.cpp:962
Mercator&#39;s (MER) projection class definition.
Interface definition for the WCS registry class.
GWcsMER(void)
Void constructor.
Definition: GWcsMER.cpp:64
GWcsMER & operator=(const GWcsMER &wcs)
Assignment operator.
Definition: GWcsMER.cpp:146
void prj_off(const double &phi0, const double &theta0) const
Compute fiducial offset to force (x,y) = (0,0) at (phi0,theta0)
Definition: GWcs.cpp:3232
virtual GWcsMER * clone(void) const
Clone Mercator&#39;s projection.
Definition: GWcsMER.cpp:203
void init_members(void)
Initialise class members.
Definition: GWcsMER.cpp:245
#define G_PRJ_X2S
Definition: GWcsMER.cpp:37
void prj_s2x(int nphi, int ntheta, int spt, int sxy, const double *phi, const double *theta, double *x, double *y, int *stat) const
Generic spherical-to-pixel projection.
Definition: GWcsMER.cpp:422
virtual std::string print(const GChatter &chatter=NORMAL) const
Print WCS information.
Definition: GWcsMER.cpp:215
void free_members(void)
Delete class members.
Definition: GWcs.cpp:1066
const GWcsMER g_wcs_mer_seed
Definition: GWcsMER.cpp:51
World Coordinate Projection registry class interface definition.
double atand(const double &value)
Compute arc tangens in degrees.
Definition: GMath.cpp:282
void copy_members(const GWcsMER &wcs)
Copy class members.
Definition: GWcsMER.cpp:257
const double deg2rad
Definition: GMath.hpp:43
void wcs_set(void) const
Setup of World Coordinate System.
Definition: GWcs.cpp:1262
GVector log(const GVector &vector)
Computes natural logarithm of vector elements.
Definition: GVector.cpp:1274
virtual GWcs & operator=(const GWcs &wcs)
Assignment operator.
Definition: GWcs.cpp:180
double m_x0
Fiducial x offset.
Definition: GWcs.hpp:215
GChatter
Definition: GTypemaps.hpp:33
virtual void clear(void)
Clear Mercator&#39;s projection.
Definition: GWcsMER.cpp:181
std::string wcs_print(const GChatter &chatter=NORMAL) const
Print WCS information.
Definition: GWcs.cpp:1642
void prj_x2s(int nx, int ny, int sxy, int spt, const double *x, const double *y, double *phi, double *theta, int *stat) const
Pixel-to-spherical deprojection.
Definition: GWcsMER.cpp:342
void prj_set(void) const
Setup of projection.
Definition: GWcsMER.cpp:291
void free_members(void)
Delete class members.
std::vector< double > m_w
Intermediate values.
Definition: GWcs.hpp:217
Abstract world coordinate system base class.
Definition: GWcs.hpp:51
int prj_bchk(const double &tol, const int &nphi, const int &ntheta, const int &spt, double *phi, double *theta, int *stat) const
Performs bounds checking on native spherical coordinates.
Definition: GWcs.cpp:3281
virtual ~GWcsMER(void)
Destructor.
Definition: GWcsMER.cpp:124
double m_y0
Fiducial y offset.
Definition: GWcs.hpp:216
void check_prj_x2s_status(const std::string &origin, const int &status, const int &number)
Checks status of GWcs::prj_x2s method.
Definition: GException.cpp:401
Exception handler interface definition.
bool m_prjset
Projection is set.
Definition: GWcs.hpp:211
void init_members(void)
Initialise class members.
GVector exp(const GVector &vector)
Computes exponential of vector elements.
Definition: GVector.cpp:1232
const double rad2deg
Definition: GMath.hpp:44
void free_members(void)
Delete class members.
Definition: GWcsMER.cpp:267
Mercator&#39;s (MER) projection class definition.
Definition: GWcsMER.hpp:43
double m_r0
Radius of the generating sphere.
Definition: GWcs.hpp:212
Mathematical function definitions.