#!/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. """ import time, math, sys, os, pickle try: from gps import * except ImportError: sys.path.append('..') from gps import * 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 ( -int(radius * math.cos(theta) + 0.5), # switch sides for a skyview! 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): gps.__init__(self) 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(lambda a, b: a.PRN - b.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', not isnan(self.fix.speed) and "%f m/s" % self.fix.speed or 'N/A') row('Course', not isnan(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', not isnan(self.fix.epx) and "%f m" % self.fix.epx or 'N/A') row('EPY', not isnan(self.fix.epy) and "%f m" % self.fix.epy or 'N/A') row('EPV', not isnan(self.fix.epv) and "%f m" % self.fix.epv or 'N/A') row('Climb', self.fix.mode == MODE_3D and not isnan(self.fix.climb) and "%f m/s" % self.fix.climb or 'N/A' ) if not (self.valid & ONLINE_SET): newstate = 0 state = "OFFLINE" else: newstate = self.fix.mode if newstate == MODE_2D: state = self.status == STATUS_DGPS_FIX and "2D DIFF FIX" or "2D FIX" elif newstate == MODE_3D: state = self.status == STATUS_DGPS_FIX and "3D DIFF FIX" or "3D FIX" else: state = "NO FIX" if newstate != self.state: self.statetimer = time.time() self.state = newstate row('State', state + " (%d secs)" % (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('E', -210, 4); ctx.strokeText('W', 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: x, y = polartocart(s.elevation, s.azimuth) 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): for prn in self.sattrack.keys(): if self.sattrack[prn].stale == 0: del self.sattrack[prn] self.needsupdate = 1 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) sat.sattrack = pickle.load(p) p.close() try: sat.run(prefix, period) except KeyboardInterrupt: # save the tracks p = open(pfile, 'w') pickle.dump(sat.sattrack, p) p.close() if __name__ == '__main__': main()