On a recent road trip around Iceland, my friends (PHP developers Andrei and Helgi) and I decided to make a travel site. We brought our cameras, GPS, and Flips, and we used PHP to: * Aggregate our experience in the form of photos (Flickr), tweets (Twitter), and videos (Vimeo). * Geotag all of these assets, so we'd remember precisely where we were. * Create a map that marks our path each day and plots our photos, tweets, and videos. We made most of this while taking in scenic views and experiencing all Iceland has to offer, and we learned a lot about geotagging, GPSes, time zones, and maps along the way. This talks shows you how to do the same, but you'll have to buy your own flight.

1. FUN WITH MAPS & PHP
Chris Shiflett — @shiflett — shiflett.org

2. Web aficionado, author, blogger, soccer player, bike
Who am I? rider, beer drinker, music lover, Brooklynite.

3. 0. Landice
Dettifoss

4. TRAVELOG
Tag everything
– #landice
Blog
– every night
Timeline Visualizations
– maps?
A!regate and Plot
– photos, tweets, videos, etc.

5. 1. Research
Sjónarsker

6. EXISTING TOOLS
GPS
– Garmin GPS 60CSx
GPSBabel
– gpsbabel.org
EveryTrail
– everytrail.com
HoudahGeo
– houdah.com/houdahGeo/

7. 2. Reykjavík
Stóra-Víti

11. 3. Photos
Kirkjufell

12. <?xml version="1.0" encoding="UTF-8"?>
<gpx
version="1.0"
creator="GPSBabel - http://gpsbabel.org/"
xmlns:xsi="http://w3.org/2001/XMLSchema-instance"
xmlns="http://topografix.com/GPX/1/0"
xsi:schemaLocation="http://topografix.com/GPX/1/0
http://topografix.com/GPX/1/0/gpx.xsd">
<time>2009-06-14T23:52:23Z</time>
<bounds minlat="64.143006038" minlon="-21.955686333"
maxlat="64.153455254" maxlon="-21.915427381"/>
<trk>
<name>14-JUN-09 01</name>
<number>1</number>
<trkseg>
<trkpt lat="64.150910676" lon="-21.946594650">
<ele>13.115112</ele>
<time>2009-06-14T21:01:25Z</time>
</trkpt>
<trkpt lat="64.150785115" lon="-21.945423950">
<ele>13.595825</ele>
<time>2009-06-14T21:02:08Z</time>
</trkpt>
</trkseg>
</trk>
</gpx>

13. PARSING GPX
$xml = simplexml_load_file('trip.gpx');
foreach($xml->trk as $part) {
foreach ($part->trkseg->trkpt as $point) {
/*
$point['lat']
$point['lon']
$point->time
$point->ele
*/
}
}

15. 4. Maps
Bláa lónið

16. Garmin GPS 60CSx Nikon D300
HoudahGeo

17. EVERYTRAIL

19. $query = $db->prepare("SELECT lat, lon
FROM points
WHERE timestamp > '$start'
AND timestamp < '$end'
ORDER BY timestamp");
$query->execute();
$points = array();
while ($row = $query->fetch()) {
$points[] = array('lat' => $row['lat'],
'lon' => $row['lon']);
}
$trip['points'] = $points;
$json = json_encode($trip);
file_put_contents("/tmp/landice-$day.json", $json);

20. // FIXME: http://tr.im/selectclosest
$sql = "SELECT lat, lon, elevation,
ABS(timestamp - :timestamp) as distance
FROM points
ORDER BY distance
LIMIT 1"
$select = $this->db->prepare($sql);
foreach ($this->photos as $photo) {
$id = (string)$photo['id'];
// Get lat and lon from points table.
$select->execute(array('timestamp' => $photo['timestamp']));
$row = $select->fetch();
$this->photos[$id]['lat'] = $row['lat'];
$this->photos[$id]['lon'] = $row['lon'];
$this->photos[$id]['elevation'] = $row['elevation'];
}

21. FLICKR API
$flickrMethod = 'flickr.photos.getInfo';
$apiUrl = "http://api.flickr.com/services/rest/?
method={$flickrMethod}&api_key={$this->apiKey}&photo_id={$id}";
$xml = simplexml_load_file($apiUrl);
$title = (string)$xml->photo->title;
$desc = (string)$xml->photo->description;

23. Google Maps OpenStreetMaps

24. 5. Challenges
Stykkishólmur

26. CLUSTERS

27. PERFORMANCE
20,000 points loaded on a
single map is very slow
You don’t need a# points
for every view
Mature solutions exist
–http://tr.im/polyline

28. 6. Storytelling
Reykjavík

33. 7. Future
Tjörnin

34. TRAILS
GPX Tracking

35. GEOLOCATION API
http://mozi#a.com/en-US/firefox/geolocation/
http://dev.w3.org/geo/api/spec-source.html

36. Click here

38. FEEDBACK?
Fo#ow me on Twitter
– @shiflett
Comment on my blog
– shiflett.org
Email me
– chris@shiflett.org

39. Thanks for listening!
Chris Shiflett — @shiflett — shiflett.org