tools/gctrackbyarc.py

   1 #!/usr/bin/env python
   2
   3 # WARNING: I haven't thought much about the best way of doing
   4 #          this. it may get lots of extra caches, or take a long
   5 #          time if your path goes thru a city.
   6 # there's probably a better algorithm.
   7
   8 # in meters.
   9 maxdist = 2500.0
  10
  11 # get geocaches, circles of "radius", then go ahead advance_dist in the track and do it again.
  12 #radius = maxdist * 2 * 0.707106 # sqrt(2)
  13 radius = maxdist * 2
  14 advance_dist = maxdist * 2
  15
  16
  17 # TODO: shell escape in case mkdtemp has unsafe chars in (unlikely)
  18
  19 class Coord:
  20   def __init__(self, lat=0.0, lon=0.0):
  21     self.lat = lat
  22     self.lon = lon
  23
  24   # diff between two coords in meters.
  25   def diff(c1,c2):
  26     from math import acos, sin, cos
  27     PIOVER180 = 3.14159265358979 / 180.0
  28     EquatorialRadius = 6378137 # WGS-84
  29     lat1 = c1.lat * PIOVER180
  30     lon1 = c1.lon * PIOVER180
  31     lat2 = c2.lat * PIOVER180
  32     lon2 = c2.lon * PIOVER180
  33     return EquatorialRadius * acos(sin(lat1)*sin(lat2)+cos(lat1)*cos(lat2)*cos(lon1-lon2));
  34
  35 def load_track ( file ):
  36   import re
  37   latlonre = re.compile("lat=['\"]([0-9\\-\\.]*?)['\"].*lon=['\"]([0-9\\-\\.]*?)['\"]")
  38   track = []
  39   for line in file:
  40     match = latlonre.search(line)
  41     if match:
  42       lat = float(match.group(1))
  43       lon = float(match.group(2))
  44       track.append ( Coord(lat,lon) )
  45   return track
  46
  47 # position inside of a track = index of trackpoint + meters past this trackpoint
  48 class TPos:
  49   def __init__(self, track):
  50     self.track = track
  51     self.n_tps = len(self.track)
  52     self.i_lasttp = 0 # index of tp before current position
  53     self.dist_past = 0 # meters past this tp
  54
  55     self.coord = Coord()
  56
  57     if self.n_tps > 0:
  58       self.coord.lat = track[0].lat
  59       self.coord.lon = track[0].lon
  60
  61     if self.n_tps > 1:
  62       self.finished = False
  63     else:
  64       self.finished = True # no tps in track, nothing to do
  65
  66   def recalculate_coord(self):
  67     if self.i_lasttp >= self.n_tps - 1:
  68       self.coord = self.track[self.n_tps - 1] # return last tp
  69       return
  70
  71     c1 = self.track[self.i_lasttp]
  72     c2 = self.track[self.i_lasttp+1]
  73
  74     # APPROXIMATE
  75     percentage_past = self.dist_past / Coord.diff ( c1, c2 )
  76     self.coord.lat = c1.lat + percentage_past * (c2.lat - c1.lat)
  77     self.coord.lon = c1.lon + percentage_past * (c2.lon - c1.lon)
  78
  79   def advance(self, distance):
  80     if self.i_lasttp >= (self.n_tps - 1):
  81       self.finished = True
  82     if self.finished:
  83       return
  84
  85     # possibility one: we don't pass a TP
  86     dist_to_next_tp = Coord.diff ( self.track[self.i_lasttp], self.track[self.i_lasttp+1] ) - self.dist_past
  87     if dist_to_next_tp > distance:
  88       self.dist_past += distance
  89       self.recalculate_coord()
  90     else:
  91       # goto beginning of next tp and try again.
  92       self.i_lasttp += 1
  93       self.dist_past = 0
  94
  95       if self.i_lasttp >= (self.n_tps - 1):
  96         self.recalculate_coord()
  97       else:
  98         self.advance ( distance - dist_to_next_tp )
  99
 100 #    dist_after_pos = dist_after_i
 101 #    if self.track[i_lasttp
 102 # TODO!
 103
 104   def end(self):
 105     return self.finished
 106
 107
 108 def get_geocaches_for(coord,radius,tmpdir,i):
 109   import os, sys
 110   MAXGCS = 100
 111   radiusinmiles = radius * 100 / 2.54 / 12 / 5280 # meters to miles
 112   gcgetstr = "gcget %f,%f %d %f > %s/%d.loc" % (coord.lat, coord.lon, MAXGCS, radius, tmpdir, i)
 113   sys.stderr.write("%s\n" % gcgetstr)
 114   os.system(gcgetstr)
 115   #print "type=\"trackpoint\" latitude=\"%f\" longitude=\"%f\"" % (coord.lat, coord.lon)
 116
 117
 118 #------------
 119
 120
 121 import sys, os
 122 tr = load_track ( sys.stdin )
 123 tpos = TPos(tr)
 124
 125 import tempfile
 126 tmpdir = tempfile.mkdtemp()
 127
 128 i = 0
 129 while not tpos.end():
 130   get_geocaches_for ( tpos.coord, radius, tmpdir, i )
 131   tpos.advance ( advance_dist )
 132   i += 1
 133 get_geocaches_for ( tpos.coord, radius, tmpdir, i )
 134
 135 ####### condense all #######
 136 gb_input_args = ["-i geo -f %s/%d.loc" % (tmpdir,j) for j in range(i)]
 137 gb_string = "gpsbabel %s -x duplicate,location -o gpx -F -" % (" ".join(gb_input_args))
 138 sys.stderr.write("\n%s\n" % gb_string)
 139 os.system(gb_string)
 140
 141 ####### delete temp files #######
 142 for j in range(i):
 143   os.sys.remove("%s/%d.loc" % (tmpdir,j))
 144 os.sys.rmdir(tmpdir)