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ttab3.c

/*============================================================================

  WCSLIB 4.8 - an implementation of the FITS WCS standard.
  Copyright (C) 1995-2011, Mark Calabretta

  This file is part of WCSLIB.

  WCSLIB is free software: you can redistribute it and/or modify it under the
  terms of the GNU Lesser General Public License as published by the Free
  Software Foundation, either version 3 of the License, or (at your option)
  any later version.

  WCSLIB 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 Lesser General Public License for
  more details.

  You should have received a copy of the GNU Lesser General Public License
  along with WCSLIB.  If not, see <http://www.gnu.org/licenses/>.

  Correspondence concerning WCSLIB may be directed to:
    Internet email: mcalabre@atnf.csiro.au
    Postal address: Dr. Mark Calabretta
                    Australia Telescope National Facility, CSIRO
                    PO Box 76
                    Epping NSW 1710
                    AUSTRALIA

  Author: Mark Calabretta, Australia Telescope National Facility
  http://www.atnf.csiro.au/~mcalabre/index.html
  $Id: ttab3.c,v 4.8.1.1 2011/08/15 08:07:06 cal103 Exp cal103 $
*=============================================================================
*
* ttab3 tests the -TAB routines using PGPLOT for graphical display.  It
* constructs a table that approximates Bonne's projection and uses it to
* draw a graticule.
*
*---------------------------------------------------------------------------*/

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <cpgplot.h>

#include <prj.h>
#include <tab.h>

#define K1 271
#define K2 235

int main()

{
  /* Set up the lookup table. */
  const int M  = 2;
  const int K[] = {K1, K2};
  const int map[] = {0, 1};
  const double crval[] = {135.0, 95.0};

  char text[80];
  int ci, i, ilat, ilng, j, k, m, stat[K2][K1], status;
  float xr[361], yr[361];
  double *dp, world[361][2], x[K1], xy[361][2], y[K2];
  struct tabprm tab;
  struct prjprm prj;

  printf(
    "Testing WCSLIB inverse coordinate lookup table routines (ttab3.c)\n"
    "-----------------------------------------------------------------\n");

  /* List status return messages. */
  printf("\nList of tab status return values:\n");
  for (status = 1; status <= 5; status++) {
    printf("%4d: %s.\n", status, tab_errmsg[status]);
  }

  printf("\n");


  /* PGPLOT initialization. */
  strcpy(text, "/xwindow");
  cpgbeg(0, text, 1, 1);
  cpgvstd();
  cpgsch(0.7f);
  cpgwnad(-135.0f, 135.0f, -95.0f, 140.0f);
  cpgbox("BC", 0.0f, 0, "BC", 0.0f, 0);

  cpgscr(0, 0.00f, 0.00f, 0.00f);
  cpgscr(1, 1.00f, 1.00f, 0.00f);
  cpgscr(2, 1.00f, 1.00f, 1.00f);
  cpgscr(3, 0.50f, 0.50f, 0.80f);
  cpgscr(4, 0.80f, 0.50f, 0.50f);
  cpgscr(5, 0.80f, 0.80f, 0.80f);
  cpgscr(6, 0.50f, 0.50f, 0.80f);
  cpgscr(7, 0.80f, 0.50f, 0.50f);
  cpgscr(8, 0.30f, 0.50f, 0.30f);


  /* Set up the lookup table. */
  tab.flag = -1;
  if ((status = tabini(1, M, K, &tab))) {
    printf("tabini ERROR %d: %s.\n", status, tab_errmsg[status]);
    return 1;
  }

  tab.M = M;
  for (m = 0; m < tab.M; m++) {
    tab.K[m] = K[m];
    tab.map[m] = map[m];
    tab.crval[m] = crval[m];

    for (k = 0; k < tab.K[m]; k++) {
      tab.index[m][k] = (double)k;
    }
  }

  /* Set up the lookup table to approximate Bonne's projection. */
  for (i = 0; i < K1; i++) {
    x[i] = 135 - i;
  }
  for (j = 0; j < K2; j++) {
    y[j] = j - 95;
  }

  prjini(&prj);
  prj.pv[1] = 35.0;
  status = bonx2s(&prj, K1, K2, 1, 2, x, y, tab.coord, tab.coord+1,
                  (int *)stat);

  dp = tab.coord;
  for (j = 0; j < K2; j++) {
    for (i = 0; i < K1; i++) {
      if (stat[j][i]) {
        *dp = 999.0;
        *(dp+1) = 999.0;
      }
      dp += 2;
    }
  }


  /* Draw meridians. */
  ci = 1;
  for (ilng = -180; ilng <= 180; ilng += 15) {
    if (++ci > 7) ci = 2;
    cpgsci(ilng?ci:1);

    for (j = 0, ilat = -90; ilat <= 90; ilat++, j++) {
      world[j][0] = (double)ilng;
      world[j][1] = (double)ilat;
    }

    /* A fudge to account for the singularity at the poles. */
    world[0][0] = 0.0;
    world[180][0] = 0.0;

    status = tabs2x(&tab, 181, 2, (double *)world, (double *)xy,
                    (int *)stat);

    k = 0;
    for (j = 0; j < 181; j++) {
      if (stat[0][j]) {
        if (k > 1) cpgline(k, xr, yr);
        k = 0;
        continue;
      }

      xr[k] = xy[j][0];
      yr[k] = xy[j][1];
      k++;
    }

    cpgline(k, xr, yr);
  }


  /* Draw parallels. */
  ci = 1;
  for (ilat = -75; ilat <= 75; ilat += 15) {
    if (++ci > 7) ci = 2;
    cpgsci(ilat?ci:1);

    for (j = 0, ilng = -180; ilng <= 180; ilng++, j++) {
      world[j][0] = (double)ilng;
      world[j][1] = (double)ilat;
    }

    status = tabs2x(&tab, 361, 2, (double *)world, (double *)xy,
                    (int *)stat);

    k = 0;
    for (j = 0; j < 361; j++) {
      if (stat[0][j]) {
        if (k > 1) cpgline(k, xr, yr);
        k = 0;
        continue;
      }

      xr[k] = xy[j][0];
      yr[k] = xy[j][1];
      k++;
    }

    cpgline(k, xr, yr);
  }

  cpgend();

  return 0;
}

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