src/vikcoord.c

   1 /*
   2  * viking -- GPS Data and Topo Analyzer, Explorer, and Manager
   3  *
   4  * Copyright (C) 2003-2005, Evan Battaglia <gtoevan@gmx.net>
   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
  22 #include <gtk/gtk.h>
  23 #include "coords.h"
  24 #include "vikcoord.h"
  25
  26 /* all coord operations MUST BE ABSTRACTED!!! */
  27
  28 void vik_coord_convert(VikCoord *coord, VikCoordMode dest_mode)
  29 {
  30   static VikCoord tmp;
  31   if ( coord->mode != dest_mode )
  32   {
  33     if ( dest_mode == VIK_COORD_LATLON ) {
  34       a_coords_utm_to_latlon ( (struct UTM *)coord, (struct LatLon *)&tmp );
  35       *((struct LatLon *)coord) = *((struct LatLon *)&tmp);
  36     } else {
  37       a_coords_latlon_to_utm ( (struct LatLon *)coord, (struct UTM *)&tmp );
  38       *((struct UTM *)coord) = *((struct UTM *)&tmp);
  39     }
  40     coord->mode = dest_mode;
  41   }
  42 }
  43
  44 void vik_coord_copy_convert(const VikCoord *coord, VikCoordMode dest_mode, VikCoord *dest)
  45 {
  46   if ( coord->mode == dest_mode ) {
  47     *dest = *coord;
  48   } else {
  49     if ( dest_mode == VIK_COORD_LATLON )
  50       a_coords_utm_to_latlon ( (struct UTM *)coord, (struct LatLon *)dest );
  51     else
  52       a_coords_latlon_to_utm ( (struct LatLon *)coord, (struct UTM *)dest );
  53     dest->mode = dest_mode;
  54   }
  55 }
  56
  57 static gdouble vik_coord_diff_safe(const VikCoord *c1, const VikCoord *c2)
  58 {
  59   static struct LatLon a, b;
  60   vik_coord_to_latlon ( c1, &a );
  61   vik_coord_to_latlon ( c2, &b );
  62   return a_coords_latlon_diff ( &a, &b );
  63 }
  64
  65 gdouble vik_coord_diff(const VikCoord *c1, const VikCoord *c2)
  66 {
  67   if ( c1->mode == c2->mode )
  68     return vik_coord_diff_safe ( c1, c2 );
  69   if ( c1->mode == VIK_COORD_UTM )
  70     return a_coords_utm_diff ( (const struct UTM *) c1, (const struct UTM *) c2 );
  71   else
  72     return a_coords_latlon_diff ( (const struct LatLon *) c1, (const struct LatLon *) c2 );
  73 }
  74
  75 void vik_coord_load_from_latlon ( VikCoord *coord, VikCoordMode mode, const struct LatLon *ll )
  76 {
  77   if ( mode == VIK_COORD_LATLON )
  78     *((struct LatLon *)coord) = *ll;
  79   else
  80     a_coords_latlon_to_utm ( ll, (struct UTM *) coord );
  81   coord->mode = mode;
  82 }
  83
  84 void vik_coord_load_from_utm ( VikCoord *coord, VikCoordMode mode, const struct UTM *utm )
  85 {
  86   if ( mode == VIK_COORD_UTM )
  87     *((struct UTM *)coord) = *utm;
  88   else
  89     a_coords_utm_to_latlon ( utm, (struct LatLon *) coord );
  90   coord->mode = mode;
  91 }
  92
  93 void vik_coord_to_latlon ( const VikCoord *coord, struct LatLon *dest )
  94 {
  95   if ( coord->mode == VIK_COORD_LATLON )
  96     *dest = *((const struct LatLon *)coord);
  97   else
  98     a_coords_utm_to_latlon ( (const struct UTM *) coord, dest );
  99 }
 100
 101 void vik_coord_to_utm ( const VikCoord *coord, struct UTM *dest )
 102 {
 103   if ( coord->mode == VIK_COORD_UTM )
 104     *dest = *((const struct UTM *)coord);
 105   else
 106     a_coords_latlon_to_utm ( (const struct LatLon *) coord, dest );
 107 }
 108
 109 gboolean vik_coord_equals ( const VikCoord *coord1, const VikCoord *coord2 )
 110 {
 111   if ( coord1->mode != coord2->mode )
 112     return FALSE;
 113   if ( coord1->mode == VIK_COORD_LATLON )
 114     return coord1->north_south == coord2->north_south && coord1->east_west == coord2->east_west;
 115   else /* VIK_COORD_UTM */
 116     return coord1->utm_zone == coord2->utm_zone && coord1->north_south == coord2->north_south && coord1->east_west == coord2->east_west;
 117 }
 118
 119 static void get_north_west(struct LatLon *center, struct LatLon *dist, struct LatLon *nw)
 120 {
 121   nw->lat = center->lat + dist->lat;
 122   nw->lon = center->lon - dist->lon;
 123   if (nw->lon < -180)
 124     nw->lon += 360.0;
 125   if (nw->lat > 90.0) {  /* over north pole */
 126     nw->lat = 180 - nw->lat;
 127     nw->lon = nw->lon - 180;
 128   }
 129 }
 130
 131 static void get_south_east(struct LatLon *center, struct LatLon *dist, struct LatLon *se)
 132 {
 133   se->lat = center->lat - dist->lat;
 134   se->lon = center->lon + dist->lon;
 135   if (se->lon > 180.0)
 136     se->lon -= 360.0;
 137   if (se->lat < -90.0) {  /* over south pole */
 138     se->lat += 180;
 139     se->lon = se->lon - 180;
 140   }
 141 }
 142
 143 void vik_coord_set_area(const VikCoord *coord, const struct LatLon *wh, VikCoord *tl, VikCoord *br)
 144 {
 145   struct LatLon center, nw, se;
 146   struct LatLon dist;
 147
 148   dist.lat = wh->lat/2;
 149   dist.lon = wh->lon/2;
 150
 151   vik_coord_to_latlon(coord, &center);
 152   get_north_west(&center, &dist, &nw);
 153   get_south_east(&center, &dist, &se);
 154
 155   *((struct LatLon *)tl) = nw;
 156   *((struct LatLon *)br) = se;
 157   tl->mode = br->mode = VIK_COORD_LATLON;
 158 }
 159
 160 gboolean vik_coord_inside(const VikCoord *coord, const VikCoord *tl, const VikCoord *br)
 161 {
 162   struct LatLon ll, tl_ll, br_ll;
 163
 164   vik_coord_to_latlon(coord, &ll);
 165   vik_coord_to_latlon(tl, &tl_ll);
 166   vik_coord_to_latlon(br, &br_ll);
 167
 168   if ((ll.lat > tl_ll.lat) || (ll.lon < tl_ll.lon))
 169     return FALSE;
 170   if ((ll.lat  < br_ll.lat) || (ll.lon > br_ll.lon))
 171     return FALSE;
 172   return TRUE;
 173 }