src/degrees_converters.c

   1 /*
   2  * viking -- GPS Data and Topo Analyzer, Explorer, and Manager
   3  *
   4  * Copyright (C) 2006-2007, Guilhem Bonnefille <guilhem.bonnefille@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21 #ifdef HAVE_CONFIG_H
  22 #include "config.h"
  23 #endif
  24
  25 #ifdef HAVE_MATH_H
  26 #include <math.h>
  27 #endif
  28 #include <glib.h>
  29 #include <string.h>
  30
  31 #define DEGREE_SYMBOL "\302\260"
  32
  33 /**
  34  * @param pos_c char for positive value
  35  * @param neg_c char for negative value
  36  */
  37 static gchar *convert_dec_to_ddd(gdouble dec, gchar pos_c, gchar neg_c)
  38 {
  39   gchar sign_c = ' ';
  40   gdouble val_d;
  41   gchar *result = NULL;
  42
  43   if ( dec > 0 )
  44     sign_c = pos_c;
  45   else if ( dec < 0 )
  46     sign_c = neg_c;
  47   else /* Nul value */
  48     sign_c = ' ';
  49
  50   /* Degree */
  51   val_d = fabs(dec);
  52
  53   /* Format */
  54   result = g_strdup_printf ( "%c%f" DEGREE_SYMBOL, sign_c, val_d );
  55   return result;
  56 }
  57
  58 gchar *convert_lat_dec_to_ddd(gdouble lat)
  59 {
  60   return convert_dec_to_ddd(lat, 'N', 'S');
  61 }
  62
  63 gchar *convert_lon_dec_to_ddd(gdouble lon)
  64 {
  65   return convert_dec_to_ddd(lon, 'E', 'W');
  66 }
  67
  68 /**
  69  * @param pos_c char for positive value
  70  * @param neg_c char for negative value
  71  */
  72 static gchar *convert_dec_to_dmm(gdouble dec, gchar pos_c, gchar neg_c)
  73 {
  74   gdouble tmp;
  75   gchar sign_c = ' ';
  76   gint val_d;
  77   gdouble val_m;
  78   gchar *result = NULL;
  79
  80   if ( dec > 0 )
  81     sign_c = pos_c;
  82   else if ( dec < 0 )
  83     sign_c = neg_c;
  84   else /* Nul value */
  85     sign_c = ' ';
  86
  87   /* Degree */
  88   tmp = fabs(dec);
  89   val_d = (gint)tmp;
  90
  91   /* Minutes */
  92   val_m = (tmp - val_d) * 60;
  93
  94   /* Format */
  95   result = g_strdup_printf ( "%c%d" DEGREE_SYMBOL "%f'",
  96                              sign_c, val_d, val_m );
  97   return result;
  98 }
  99
 100 gchar *convert_lat_dec_to_dmm(gdouble lat)
 101 {
 102   return convert_dec_to_dmm(lat, 'N', 'S');
 103 }
 104
 105 gchar *convert_lon_dec_to_dmm(gdouble lon)
 106 {
 107   return convert_dec_to_dmm(lon, 'E', 'W');
 108 }
 109
 110 /**
 111  * @param pos_c char for positive value
 112  * @param neg_c char for negative value
 113  */
 114 static gchar *convert_dec_to_dms(gdouble dec, gchar pos_c, gchar neg_c)
 115 {
 116   gdouble tmp;
 117   gchar sign_c = ' ';
 118   gint val_d, val_m;
 119   gdouble val_s;
 120   gchar *result = NULL;
 121
 122   if ( dec > 0 )
 123     sign_c = pos_c;
 124   else if ( dec < 0 )
 125     sign_c = neg_c;
 126   else /* Nul value */
 127     sign_c = ' ';
 128
 129   /* Degree */
 130   tmp = fabs(dec);
 131   val_d = (gint)tmp;
 132
 133   /* Minutes */
 134   tmp = (tmp - val_d) * 60;
 135   val_m = (gint)tmp;
 136
 137   /* Minutes */
 138   val_s = (tmp - val_m) * 60;
 139
 140   /* Format */
 141   result = g_strdup_printf ( "%c%d" DEGREE_SYMBOL "%d'%f\"",
 142                              sign_c, val_d, val_m, val_s );
 143   return result;
 144 }
 145
 146 gchar *convert_lat_dec_to_dms(gdouble lat)
 147 {
 148   return convert_dec_to_dms(lat, 'N', 'S');
 149 }
 150
 151 gchar *convert_lon_dec_to_dms(gdouble lon)
 152 {
 153   return convert_dec_to_dms(lon, 'E', 'W');
 154 }
 155
 156 gdouble convert_dms_to_dec(const gchar *dms)
 157 {
 158         gdouble d = 0.0; /* Degree */
 159         gdouble m = 0.0; /* Minutes */
 160         gdouble s = 0.0; /* Seconds */
 161         gint neg = FALSE;
 162         gdouble result;
 163
 164         if (dms != NULL) {
 165                 int nbFloat = 0;
 166                 const gchar *ptr, *endptr;
 167
 168                 // Compute the sign
 169                 // It is negative if:
 170                 // - the '-' sign occurs
 171                 // - it is a west longitude or south latitude
 172                 if (strpbrk (dms, "-wWsS") != NULL)
 173                     neg = TRUE;
 174
 175                 // Peek the différent components
 176                 endptr = dms;
 177                 do {
 178                         gdouble value;
 179                         ptr = strpbrk (endptr, "0123456789,.");
 180                         if (ptr != NULL) {
 181                                 value = g_strtod(ptr, &endptr);
 182                         nbFloat++;
 183                 switch(nbFloat) {
 184                         case 1:
 185                                 d = value;
 186                                 break;
 187                         case 2:
 188                                 m = value;
 189                                 break;
 190                         case 3:
 191                                 s = value;
 192                                 break;
 193                 }
 194                         }
 195                 } while (ptr != NULL && endptr != NULL);
 196         }
 197
 198         // Compute the result
 199         result = d + m/60 + s/3600;
 200
 201         if (neg) result = - result;
 202
 203         return result;
 204 }