#!/usr/bin/env python
import json, math, sys
from urllib2 import urlopen
from contextlib import closing
def greatcircle(lat0, lon0, lat1, lon1):
lat0 = lat0 * math.pi / 180.0;
lon0 = lon0 * math.pi / 180.0;
lat1 = lat1 * math.pi / 180.0;
lon1 = lon1 * math.pi / 180.0;
return 6371e3 * math.acos(math.sin(lat0) * math.sin(lat1) + math.cos(lat0) * math.cos(lat1) * math.cos(abs(lon0 - lon1)))
def get_max_range(baseurl):
with closing(urlopen(baseurl + '/data/receiver.json', None, 5.0)) as f:
receiver = json.load(f)
if not (receiver.has_key('lat') and receiver.has_key('lon')):
return None
rlat = receiver['lat']
rlon = receiver['lon']
maxrange = None
with closing(urlopen(baseurl + '/data/aircraft.json', None, 5.0)) as f:
aircraft = json.load(f)
for ac in aircraft['aircraft']:
if ac.has_key('seen_pos') and ac['seen_pos'] < 300:
alat = ac['lat']
alon = ac['lon']
distance = greatcircle(rlat, rlon, alat, alon)
if maxrange is None or distance > maxrange:
maxrange = distance
return maxrange
if __name__ == '__main__':
import sys
baseurl = sys.argv[1]
maxrange = get_max_range(baseurl)
if maxrange is None: print 'UNKNOWN'
else: print '%.1f' % (maxrange / 1852.0)
print '0'
print '0'
print 'dump1090 at ' + baseurl
