gpsd.php

gpsd, a popular GPS daemon.

<?php

#$CSK: gpsd.php,v 1.39 2006/11/21 22:31:10 ckuethe Exp $

# Copyright (c) 2006 Chris Kuethe <[e-mail]>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

global $head, $blurb, $title, $googlemap, $autorefresh, $footer, $gmap_key;
global $GPS, $server, $advertise, $port, $magic, $swap_ew, $magic;
$magic = 1; # leave this set to 1

if (!file_exists("gpsd_config.inc"))
	write_config();

require_once("gpsd_config.inc");

# sample data
$resp = 'GPSD,S=2,P=53.527167 -113.530168,A=704.542,M=3,Q=10 1.77 0.80 0.66 0.61 1.87,Y=MID9 1158081774.000000 12:25 24 70 42 1:4 13 282 36 1:23 87 196 48 1:6 9 28 29 1:16 54 102 47 1:20 34 190 45 1:2 12 319 36 1:13 52 292 46 1:24 12 265 0 0:1 8 112 41 1:27 16 247 40 1:122 23 213 31 0:';

# if we're passing in a query, let's unpack and use it
if (isset($_GET['imgdata']) && isset($_GET['op']) && ($_GET['op'] == 'view')){
	$resp = base64_decode($_GET['imgdata']);
	if ($resp){
		gen_image($resp);
		exit(0);
	}
} else {
	if (isset($_GET['host']))
		if (!preg_match('/[^a-zA-Z0-9\.-]/', $_GET['host']))
			$server = $_GET['host'];

	if (isset($_GET['port']))
		if (!preg_match('/\D/', $_GET['port']) && ($port>0) && ($port<65536))
			$port = $_GET['port'];

	if ($magic){
		$sock = @fsockopen($server, $port, $errno, $errstr, 2);
		@fwrite($sock, "J=1,W=1\n");	# watcher mode and buffering
		$z = 0;
		do {
			$resp = @fread($sock, 384);
			$z++;
		} while ((strncmp($resp, 'GPSD,O=', 7) || (
			strncmp($resp, 'GPSD,O=', 7) == 0 &&
			strlen($resp) <= 8)) &&
			$z < 6);
		@fwrite($sock, "SPAMQY\n");	# Query what we actually want
		# the O report doesn't give us satellite usage or DOP
		$resp = @fread($sock, 384);
		@fclose($sock);
	}
}

if (isset($_GET['op']) && ($_GET['op'] == 'view')){
	gen_image($resp);
} else {
	parse_pvt($resp);
	write_html($resp);
}

exit(0);

###########################################################################
function colorsetup($im){
	$C['white']	= imageColorAllocate($im, 255, 255, 255);
	$C['ltgray']	= imageColorAllocate($im, 191, 191, 191);
	$C['mdgray']	= imageColorAllocate($im, 127, 127, 127);
	$C['dkgray']	= imageColorAllocate($im, 63, 63, 63);
	$C['black']	= imageColorAllocate($im, 0, 0, 0);
	$C['red']	= imageColorAllocate($im, 255, 0, 0);
	$C['brightgreen'] = imageColorAllocate($im, 0, 255, 0);
	$C['darkgreen']	= imageColorAllocate($im, 0, 192, 0);
	$C['blue']	= imageColorAllocate($im, 0, 0, 255);
	$C['cyan']	= imageColorAllocate($im, 0, 255, 255);
	$C['magenta']	= imageColorAllocate($im, 255, 0, 255);
	$C['yellow']	= imageColorAllocate($im, 255, 255, 0);
	$C['orange']	= imageColorAllocate($im, 255, 128, 0);

	return $C;
}

function legend($im, $sz, $C){
	$r = 30;
	$fn = 5;
	$x = $sz - (4*$r+7) - 2;
	$y = $sz - $r - 3;

	imageFilledRectangle($im, $x, $y, $x + 4*$r + 7, $y + $r +1, $C['dkgray']);
	imageRectangle($im, $x+0*$r+1, $y+1, $x + 1*$r + 0, $y + $r, $C['red']);
	imageRectangle($im, $x+1*$r+2, $y+1, $x + 2*$r + 2, $y + $r, $C['yellow']);
	imageRectangle($im, $x+2*$r+4, $y+1, $x + 3*$r + 4, $y + $r, $C['darkgreen']);
	imageRectangle($im, $x+4*$r+6, $y+1, $x + 3*$r + 6, $y + $r, $C['brightgreen']);
	imageString($im, $fn, $x+3+0*$r, $y+$r/3, "<30", $C['red']);
	imageString($im, $fn, $x+5+1*$r, $y+$r/3, "30+", $C['yellow']);
	imageString($im, $fn, $x+7+2*$r, $y+$r/3, "35+", $C['darkgreen']);
	imageString($im, $fn, $x+9+3*$r, $y+$r/3, "40+", $C['brightgreen']);
}

function radial($angle, $sz){
	#turn into radians
	$angle = deg2rad($angle);

	# determine length of radius
	$r = $sz * 0.5 * 0.95;

	# and convert length/azimuth to cartesian
	$x0 = sprintf("%d", (($sz * 0.5) - ($r * cos($angle))));
	$y0 = sprintf("%d", (($sz * 0.5) - ($r * sin($angle))));
	$x1 = sprintf("%d", (($sz * 0.5) + ($r * cos($angle))));
	$y1 = sprintf("%d", (($sz * 0.5) + ($r * sin($angle))));

	return array($x0, $y0, $x1, $y1);
}

function azel2xy($az, $el, $sz){
	global $swap_ew;
	#rotate coords... 90deg W = 180deg trig
	$az += 270;

	#turn into radians
	$az = deg2rad($az);

	# determine length of radius
	$r = $sz * 0.5 * 0.95;
	$r -= ($r * ($el/90));

	# and convert length/azimuth to cartesian
	$x = sprintf("%d", (($sz * 0.5) + ($r * cos($az))));
	$y = sprintf("%d", (($sz * 0.5) + ($r * sin($az))));
	if ($swap_ew == 0)
		$x = $sz - $x;

	return array($x, $y);
}

function splot($im, $sz, $C, $e){
	list($sv, $el, $az, $snr, $u) = $e;

	if ((0 == $sv) || (0 == $az + $el + $snr) ||
	    ($az < 0) || ($el < 0))
		return;

	$color = $C['brightgreen'];
	if ($snr < 40)
		$color = $C['darkgreen'];
	if ($snr < 35)
		$color = $C['yellow'];
	if ($snr < 30)
		$color = $C['red'];
	if ($el<10)
		$color = $C['blue'];
	if ($snr < 10)
		$color = $C['black'];

	list($x, $y) = azel2xy($az, $el, $sz);

	$r = 12;
	if (isset($_GET['sz']) && ($_GET['sz'] == 'small'))
		$r = 8;

	imageString($im, 3, $x+4, $y+4, $sv, $C['black']);
	if ($u)
		imageFilledArc($im, $x, $y, $r, $r, 0, 360, $color, 0);
	else
		if ($sv > 32) {
			imageDiamond($im, $x, $y, $r, $color);
		} else {
			imageArc($im, $x, $y, $r, $r, 0, 360, $color);
		}
}

function imageDiamond($im, $x, $y, $r, $color){
	$t = $r/2;
	# this lunacy is because imagesetthickness doesn't seem to work
	$vx = array ( $x+$t, $y, $x, $y+$t, $x-$t, $y, $x, $y-$t );
	imagepolygon($im, $vx, 4, $color);
	$t--;
	$vx = array ( $x+$t, $y, $x, $y+$t, $x-$t, $y, $x, $y-$t );
	imagepolygon($im, $vx, 4, $color);
	$t--;
	$vx = array ( $x+$t, $y, $x, $y+$t, $x-$t, $y, $x, $y-$t );
	imagepolygon($im, $vx, 4, $color);
}

function elevation($im, $sz, $C, $a){
	$b = 90 - $a;
	$a = $sz * 0.95 * ($a/180);
	imageArc($im, $sz/2, $sz/2, $a*2, $a*2, 0, 360, $C['ltgray']);
	$x = $sz/2 - 16;
	$y = $sz/2 - $a;
	imageString($im, 2, $x, $y, $b, $C['ltgray']);
}

function skyview($im, $sz, $C){
	global $swap_ew;
	$a = 90; $a = $sz * 0.95 * ($a/180);
	imageFilledArc($im, $sz/2, $sz/2, $a*2, $a*2, 0, 360, $C['mdgray'], 0);
	imageArc($im, $sz/2, $sz/2, $a*2, $a*2, 0, 360, $C['black']);
	$x = $sz/2 - 16; $y = $sz/2 - $a;
	imageString($im, 2, $x, $y, "0", $C['ltgray']);

	$a = 85; $a = $sz * 0.95 * ($a/180);
	imageFilledArc($im, $sz/2, $sz/2, $a*2, $a*2, 0, 360, $C['white'], 0);
	imageArc($im, $sz/2, $sz/2, $a*2, $a*2, 0, 360, $C['ltgray']);
	imageString($im, 1, $sz/2 - 6, $sz+$a, '5', $C['black']);
	$x = $sz/2 - 16; $y = $sz/2 - $a;
	imageString($im, 2, $x, $y, "5", $C['ltgray']);

	for($i = 0; $i < 180; $i += 15){
		list($x0, $y0, $x1, $y1) = radial($i, $sz);
		imageLine($im, $x0, $y0, $x1, $y1, $C['ltgray']);
	}

	for($i = 15; $i < 90; $i += 15)
		elevation($im, $sz, $C, $i);

	$x = $sz/2 - 16; $y = $sz/2 - 8;
	/* imageString($im, 2, $x, $y, "90", $C['ltgray']); */

	imageString($im, 4, $sz/2 + 4, 2        , 'N', $C['black']);
	imageString($im, 4, $sz/2 + 4, $sz - 16 , 'S', $C['black']);
	if ($swap_ew == 0){
		imageString($im, 4, 4        , $sz/2 + 4, 'E', $C['black']);
		imageString($im, 4, $sz - 10 , $sz/2 + 4, 'W', $C['black']);
	} else {
		imageString($im, 4, 4        , $sz/2 + 4, 'W', $C['black']);
		imageString($im, 4, $sz - 10 , $sz/2 + 4, 'E', $C['black']);
	}
}

function gen_image($resp){
	global $magic;

	$sz = 640;
	if (isset($_GET['sz']) && ($_GET['sz'] == 'small'))
		$sz = 240;

	if (!preg_match('/,Y=\S+ [0-9\.]+ (\d+):/', $resp, $m))
		die("can't parse gpsd's response");
	$n = $m[1];	

	$im = imageCreate($sz, $sz);
	$C = colorsetup($im);
	skyview($im, $sz, $C);
	if ($sz > 240)
		legend($im, $sz, $C);

	$s = explode(':', $resp);
	for($i = 1; $i <= $n; $i++){
		$e = explode(' ', $s[$i]);
		splot($im, $sz, $C, $e);
	}

	header("Content-type: image/png");
	imagePNG($im);
	imageDestroy($im);
}

function clearstate(){
	global $GPS;

	$GPS['loc'] = '';
	$GPS['alt'] = 'Unavailable';
	$GPS['lat'] = 'Unavailable';
	$GPS['lon'] = 'Unavailable';
	$GPS['sat'] = 'Unavailable';
	$GPS['hdop'] = 'Unavailable';
	$GPS['dgps'] = 'Unavailable';
	$GPS['fix'] = 'Unavailable';
	$GPS['gt'] = '';
	$GPS['lt'] = '';
}

function dfix($x, $y, $z){
	if ($x < 0){
		$x = sprintf("%f %s", -1 * $x, $z);
	} else {
		$x = sprintf("%f %s", $x, $y);
	}
	return $x;
}

function parse_pvt($resp){
	global $GPS, $magic;

	clearstate();

	if (strlen($resp)){