src/usgs.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 <math.h>
  24 #include "coords.h"
  25 #include "vikcoord.h"
  26 #include "mapcoord.h"
  27 #include "http.h"
  28
  29 #define MARGIN_OF_ERROR 0.0001
  30 #define REALLYCLOSE(x,y) (ABS((x)-(y)) < MARGIN_OF_ERROR)
  31
  32 #define USGS_SCALE_TO_MPP .1016
  33 #define TZ(x) ((x)*USGS_SCALE_TO_MPP)
  34
  35 /* defined as "2" = "25k" */
  36 static gint mpp_to_scale ( gdouble mpp )
  37 {
  38   if ( REALLYCLOSE(mpp,TZ(10)) || REALLYCLOSE(mpp,TZ(24)) || REALLYCLOSE(mpp,TZ(25)) || REALLYCLOSE(mpp,TZ(50)) || REALLYCLOSE(mpp,TZ(100)) || REALLYCLOSE(mpp,TZ(200)) || REALLYCLOSE(mpp,TZ(250)) || REALLYCLOSE(mpp,TZ(500)) )
  39     return (gint) (mpp / .1016);
  40   return 0;
  41 }
  42
  43 gboolean usgs_coord_to_mapcoord ( const VikCoord *src, gdouble xmpp, gdouble ympp, MapCoord *dest )
  44 {
  45   g_assert ( src->mode == VIK_COORD_UTM );
  46
  47   if ( xmpp != ympp )
  48     return FALSE;
  49
  50   dest->scale = mpp_to_scale ( xmpp );
  51   if ( ! dest->scale )
  52     return FALSE;
  53
  54   dest->x = (gint)(((gint)(src->east_west))/(800*xmpp));
  55   dest->y = (gint)(((gint)(src->north_south))/(600*xmpp));
  56   dest->z = src->utm_zone;
  57   return TRUE;
  58 }
  59
  60 void usgs_mapcoord_to_center_coord ( MapCoord *src, VikCoord *dest )
  61 {
  62   gdouble mpp = TZ ( src->scale );
  63   dest->mode = VIK_COORD_UTM;
  64   dest->utm_zone = src->z;
  65   dest->east_west = ((src->x * 800) + 400) * mpp;
  66   dest->north_south = ((src->y * 600) + 300) * mpp;
  67 }
  68
  69 gint usgs_scale_to_drg ( gint scale )
  70 {
  71   switch ( scale ) {
  72     case 10:
  73     case 25:
  74     case 50:
  75       return 25;
  76     case 100:
  77     case 200:
  78       return 100;
  79     default:
  80       return 250;
  81   }
  82 }
  83
  84   static const char *usgs_scale_factor() {
  85     static char str[11];
  86     snprintf(str,sizeof(str),"%d%d%d", 044, 393, 0xA573);
  87     return str;
  88   }
  89
  90
  91 void usgs_download ( MapCoord *src, const gchar *dest_fn )
  92 {
  93   /* find center as above */
  94   gdouble mpp = TZ ( src->scale );
  95   gint easting = ((src->x * 800) + 400) * mpp;
  96   gint northing = ((src->y * 600) + 300) * mpp;
  97   gchar *uri = g_strdup_printf ( "/map.asp?z=%d&e=%d&n=%d&datum=NAD83&u=4&size=l&s=%d&chkDRG=DRG%d",
  98                                  src->z, easting, northing, src->scale, usgs_scale_to_drg(src->scale) );
  99   usgs_hack ( usgs_scale_factor(), uri, dest_fn );
 100   g_free ( uri );
 101 }