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#!/usr/bin/env python
# encoding: utf-8
"""webgps.py
This is a Python port of webgps.c
from http://www.wireless.org.au/~jhecker/gpsd/
by Beat Bolli <me+gps@drbeat.li>
It creates a skyview of the currently visible GPS satellites and their tracks
over a time period.
Usage:
./webgps.py [duration]
duration may be
- a number of seconds
- a number followed by a time unit ('s' for secinds, 'm' for minutes,
'h' for hours or 'd' for days, e.g. '4h' for a duration of four hours)
- the letter 'c' for continuous operation
If duration is missing, the current skyview is generated and webgps.py exits
immediately. This is the same as giving a duration of 0.
If a duration is given, webgps.py runs for this duration and generates the
tracks of the GPS satellites in view. If the duration is the letter 'c',
the script never exits and continuously updates the skyview.
webgps.py generates two files: a HTML5 file that can be browsed, and a
JavaScript file that contains the drawing commands for the skyview. The HTML5
file auto-refreshes every five minutes. The generated file names are
"gpsd-<duration>.html" and "gpsd-<duration>.js".
If webgps.py is interrupted with Ctrl-C before the duration is over, it saves
the current tracks into the file "tracks.p". This is a Python "pickle" file.
If this file is present on start of webgps.py, it is loaded. This allows to
restart webgps.py without losing accumulated satellite tracks.
"""
# This file is Copyright (c) 2010-2018 by the GPSD project
# SPDX-License-Identifier: BSD-2-clause
from __future__ import absolute_import, print_function, division
import math
import os
import pickle
import sys
import time
from gps import *
gps_version = '3.19-dev'
if gps.__version__ != gps_version:
sys.stderr.write("webgps.py: ERROR: need gps module version %s, got %s\n" %
(gps_version, gps.__version__))
sys.exit(1)
TRACKMAX = 1024
STALECOUNT = 10
DIAMETER = 200
def polartocart(el, az):
radius = DIAMETER * (1 - el / 90.0) # * math.cos(Deg2Rad(float(el)))
theta = Deg2Rad(float(az - 90))
return (
# Changed this back to normal orientation - fw
int(radius * math.cos(theta) + 0.5),
int(radius * math.sin(theta) + 0.5)
)
class Track:
'''Store the track of one satellite.'''
def __init__(self, prn):
self.prn = prn
self.stale = 0
self.posn = [] # list of (x, y) tuples
def add(self, x, y):
pos = (x, y)
self.stale = STALECOUNT
if not self.posn or self.posn[-1] != pos:
self.posn.append(pos)
if len(self.posn) > TRACKMAX:
self.posn = self.posn[-TRACKMAX:]
return 1
return 0
def track(self):
'''Return the track as canvas drawing operations.'''
return('M(%d,%d); ' % self.posn[0] + ''.join(['L(%d,%d); ' %
p for p in self.posn[1:]]))
class SatTracks(gps):
'''gpsd client writing HTML5 and <canvas> output.'''
def __init__(self):
super(SatTracks, self).__init__()
self.sattrack = {} # maps PRNs to Tracks
self.state = None
self.statetimer = time.time()
self.needsupdate = 0
def html(self, fh, jsfile):
fh.write("""<!DOCTYPE html>
<html>
<head>
\t<meta http-equiv=Refresh content=300>
\t<meta charset='utf-8'>
\t<title>GPSD Satellite Positions and Readings</title>
\t<style type='text/css'>
\t\t.num td { text-align: right; }
\t\tth { text-align: left; }
\t</style>
\t<script src='%s'></script>
</head>
<body>
\t<table border=1>
\t\t<tr>
\t\t\t<td>
\t\t\t\t<table border=0 class=num>
\t\t\t\t\t<tr><th>PRN:</th><th>Elev:</th><th>Azim:</th><th>SNR:</th>
<th>Used:</th></tr>
""" % jsfile)
sats = self.satellites[:]
sats.sort(key=lambda x: x.PRN)
for s in sats:
fh.write("\t\t\t\t\t<tr><td>%d</td><td>%d</td><td>%d</td>"
"<td>%d</td><td>%s</td></tr>\n" %
(s.PRN, s.elevation, s.azimuth, s.ss,
s.used and 'Y' or 'N'))
fh.write("\t\t\t\t</table>\n\t\t\t\t<table border=0>\n")
def row(l, v):
fh.write("\t\t\t\t\t<tr><th>%s:</th><td>%s</td></tr>\n" % (l, v))
def deg_to_str(a, hemi):
return '%.6f %c' % (abs(a), hemi[a < 0])
row('Time', self.utc or 'N/A')
if self.fix.mode >= MODE_2D:
row('Latitude', deg_to_str(self.fix.latitude, 'SN'))
row('Longitude', deg_to_str(self.fix.longitude, 'WE'))
row('Altitude', self.fix.mode == MODE_3D and "%f m" %
self.fix.altitude or 'N/A')
row('Speed', isfinite(self.fix.speed) and "%f m/s" %
self.fix.speed or 'N/A')
row('Course', isfinite(self.fix.track) and "%f°" %
self.fix.track or 'N/A')
else:
row('Latitude', 'N/A')
row('Longitude', 'N/A')
row('Altitude', 'N/A')
row('Speed', 'N/A')
row('Course', 'N/A')
row('EPX', isfinite(self.fix.epx) and "%f m" % self.fix.epx or 'N/A')
row('EPY', isfinite(self.fix.epy) and "%f m" % self.fix.epy or 'N/A')
row('EPV', isfinite(self.fix.epv) and "%f m" % self.fix.epv or 'N/A')
row('Climb', self.fix.mode == MODE_3D and isfinite(self.fix.climb) and
"%f m/s" % self.fix.climb or 'N/A')
state = "INIT"
if not (self.valid & ONLINE_SET):
newstate = 0
state = "OFFLINE"
else:
newstate = self.fix.mode
if newstate == MODE_2D:
state = "2D FIX"
elif newstate == MODE_3D:
state = "3D FIX"
else:
state = "NO FIX"
if newstate != self.state:
self.statetimer = time.time()
self.state = newstate
row('State', "%s (%d secs)" % (state, time.time() - self.statetimer))
fh.write("""\t\t\t\t</table>
\t\t\t</td>
\t\t\t<td>
\t\t\t\t<canvas id=satview width=425 height=425>
\t\t\t\t\t<p>Your browser needs HTML5 <canvas> support to display
the satellite view correctly.</p>
\t\t\t\t</canvas>
\t\t\t\t<script type='text/javascript'>draw_satview();</script>
\t\t\t</td>
\t\t</tr>
\t</table>
</body>
</html>
""")
def js(self, fh):
fh.write("""// draw the satellite view
function draw_satview() {
var c = document.getElementById('satview');
if (!c.getContext) return;
var ctx = c.getContext('2d');
if (!ctx) return;
var circle = Math.PI * 2,
M = function (x, y) { ctx.moveTo(x, y); },
L = function (x, y) { ctx.lineTo(x, y); };
ctx.save();
ctx.clearRect(0, 0, c.width, c.height);
ctx.translate(210, 210);
// grid and labels
ctx.strokeStyle = 'black';
ctx.beginPath();
ctx.arc(0, 0, 200, 0, circle, 0);
ctx.stroke();
ctx.beginPath();
ctx.strokeText('N', -4, -202);
ctx.strokeText('W', -210, 4);
ctx.strokeText('E', 202, 4);
ctx.strokeText('S', -4, 210);
ctx.strokeStyle = 'grey';
ctx.beginPath();
ctx.arc(0, 0, 100, 0, circle, 0);
M(2, 0);
ctx.arc(0, 0, 2, 0, circle, 0);
ctx.stroke();
ctx.strokeStyle = 'lightgrey';
ctx.save();
ctx.beginPath();
M(0, -200); L(0, 200); ctx.rotate(circle / 8);
M(0, -200); L(0, 200); ctx.rotate(circle / 8);
M(0, -200); L(0, 200); ctx.rotate(circle / 8);
M(0, -200); L(0, 200);
ctx.stroke();
ctx.restore();
// tracks
ctx.lineWidth = 0.6;
ctx.strokeStyle = 'red';
""")
# Draw the tracks
for t in self.sattrack.values():
if t.posn:
fh.write(" ctx.globalAlpha = %s; ctx.beginPath(); "
"%sctx.stroke();\n" %
(t.stale == 0 and '0.66' or '1', t.track()))
fh.write("""
// satellites
ctx.lineWidth = 1;
ctx.strokeStyle = 'black';
""")
# Draw the satellites
for s in self.satellites:
el, az = s.elevation, s.azimuth
if el == 0 and az == 0:
continue # Skip satellites with unknown position
x, y = polartocart(el, az)
fill = not s.used and 'lightgrey' or \
s.ss < 30 and 'red' or \
s.ss < 35 and 'yellow' or \
s.ss < 40 and 'green' or 'lime'
# Center PRNs in the marker
offset = s.PRN < 10 and 3 or s.PRN >= 100 and -3 or 0
fh.write(" ctx.beginPath(); ctx.fillStyle = '%s'; " % fill)
if s.PRN > 32: # Draw a square for SBAS satellites
fh.write("ctx.rect(%d, %d, 16, 16); " % (x - 8, y - 8))
else:
fh.write("ctx.arc(%d, %d, 8, 0, circle, 0); " % (x, y))
fh.write("ctx.fill(); ctx.stroke(); "
"ctx.strokeText('%s', %d, %d);\n" %
(s.PRN, x - 6 + offset, y + 4))
fh.write("""
ctx.restore();
}
""")
def make_stale(self):
for t in self.sattrack.values():
if t.stale:
t.stale -= 1
def delete_stale(self):
stales = []
for prn in self.sattrack.keys():
if self.sattrack[prn].stale == 0:
stales.append(prn)
self.needsupdate = 1
for prn in stales:
del self.sattrack[prn]
def insert_sat(self, prn, x, y):
try:
t = self.sattrack[prn]
except KeyError:
self.sattrack[prn] = t = Track(prn)
if t.add(x, y):
self.needsupdate = 1
def update_tracks(self):
self.make_stale()
for s in self.satellites:
x, y = polartocart(s.elevation, s.azimuth)
self.insert_sat(s.PRN, x, y)
self.delete_stale()
def generate_html(self, htmlfile, jsfile):
fh = open(htmlfile, 'w')
self.html(fh, jsfile)
fh.close()
def generate_js(self, jsfile):
fh = open(jsfile, 'w')
self.js(fh)
fh.close()
def run(self, suffix, period):
jsfile = 'gpsd' + suffix + '.js'
htmlfile = 'gpsd' + suffix + '.html'
if period is not None:
end = time.time() + period
self.needsupdate = 1
self.stream(WATCH_ENABLE | WATCH_NEWSTYLE)
for report in self:
if report['class'] not in ('TPV', 'SKY'):
continue
self.update_tracks()
if self.needsupdate:
self.generate_js(jsfile)
self.needsupdate = 0
self.generate_html(htmlfile, jsfile)
if period is not None and (
period <= 0 and self.fix.mode >= MODE_2D or
period > 0 and time.time() > end
):
break
def main():
argv = sys.argv[1:]
factors = {
's': 1, 'm': 60, 'h': 60 * 60, 'd': 24 * 60 * 60
}
arg = argv and argv[0] or '0'
if arg[-1:] in factors.keys():
period = int(arg[:-1]) * factors[arg[-1]]
elif arg == 'c':
period = None
else:
period = int(arg)
prefix = '-' + arg
sat = SatTracks()
# restore the tracks
pfile = 'tracks.p'
if os.path.isfile(pfile):
p = open(pfile, 'rb')
try:
sat.sattrack = pickle.load(p)
except ValueError:
print("Ignoring incompatible tracks file.", file=sys.stderr)
p.close()
try:
sat.run(prefix, period)
except KeyboardInterrupt:
# save the tracks
p = open(pfile, 'wb')
# No protocol is backward-compatible from Python 3 to Python 2,
# so we just use the default and punt at load time if needed.
pickle.dump(sat.sattrack, p)
p.close()
if __name__ == '__main__':
main()
|
