#!/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 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-.html" and "gpsd-.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. """ from __future__ import absolute_import, print_function, division import math import os import pickle import sys import time from gps import * gps_version = '3.18' 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 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(""" \t \t \tGPSD Satellite Positions and Readings \t \t \t \t\t \t\t\t \t\t\t \t\t \t
\t\t\t\t \t\t\t\t\t """ % jsfile) sats = self.satellites[:] sats.sort(key=lambda x: x.PRN) for s in sats: fh.write("\t\t\t\t\t" "\n" % (s.PRN, s.elevation, s.azimuth, s.ss, s.used and 'Y' or 'N')) fh.write("\t\t\t\t
PRN:Elev:Azim:SNR: Used:
%d%d%d%d%s
\n\t\t\t\t\n") def row(l, v): fh.write("\t\t\t\t\t\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
%s:%s
\t\t\t		 \t\t\t\t \t\t\t\t\t

Your browser needs HTML5 <canvas> support to display the satellite view correctly.

\t\t\t\t \t\t\t\t \t\t\t
""") 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()