This document describes using GeoRSS to display train locations and information in real-time on a map using OpenLayers. It discusses how GeoRSS encodes geographical data in RSS feeds and the OpenLayers classes that can be used to read GeoRSS feeds and display the features on a map. It also provides examples of GeoRSS feeds that could be used to show all trains or detailed information about a single train, and code samples for setting up OpenLayers layers to visualize the feeds.

1. Presenting trains in real-time
in OpenLayers via GeoRSS
Janne Kovanen
Finnish Geodetic Institute
Department of Geoinformatics and Cartography
GI Norden June 8–9, 2011, Turku, Finland

2. GeoRSS
 An geographical syntax in RSS feeds (XML)
 The coordinate reference system is WGS84
 A coordinate conversion to a plane coordinate
reference system is mostly required
 Notice! In web browsers you typically see the
interpretation of a RSS feed reader
 view-source:http://188.117.35.14/TrainRSS/
TrainService.svc/trainInfo?train=P704
 Updating from an app requires a proxy
 Several exists (web )
Workshop on Open Location Data 2011 Finnish Geodetic Institute 2
janne.kovanen@fgi.fi

3. GeoRSS and GeoRSS-Simple
 For Atom 1.0, RSS 2.0 and RSS 1.0
 GML content
 <georss:where>
<gml:Point>
<gml:pos>45.256 -71.92</gml:pos>
</gml:Point>
</georss:where>
 Too complex? Simpler alternative:
 <georss:point>60.1 54.2</georss:point>
 <georss:line>45.256 -110.45 46.46 -109.48 43.84 -109.86</
georss:line>
 <georss:polygon>45.256 -110.45 46.46 -109.48 43.84 -109.86
45.256 -110.45</georss:polygon>
Workshop on Open Location Data 2011 Finnish Geodetic Institute 3
janne.kovanen@fgi.fi

4. OpenLayers and GeoRSS
 OpenLayers.Layer.GeoRSS
 Extends a layer for markers
 As such OL downloads the feed only ones
 Features are stored as OpenLayers.Feature
 Does not contains methods for handling features!
 OpenLayers.Format.GeoRSS
 Format for reading GeoRSS
 Only reads such as a title, description and geometry
 Features are handled as OpenLayers.Feature.Vector
 OpenLayers.LonLat vs. OpenLayers.Geometry
Workshop on Open Location Data 2011 Finnish Geodetic Institute 4
janne.kovanen@fgi.fi

5. “Trains on a map” interface
All trains
<rss version="2.0">
<channel xmlns:georss="http://www.georss.org/georss">
<title>Train Feed</title>
<description>All trains feed</description>
<lastBuildDate>Tue, 20 Sep 2011 15:00:35 +0300</lastBuildDate>
<category>Train System</category>
<item>
<guid isPermaLink="false">H355</guid>
<category>1</category><title>H 355</title>
<description>Summary</description>
<pubDate>Tue, 20 Sep 2011 15:00:35 +0300</pubDate>
<georss:point>60.6302800000001 26.8929000000001</georss:point>
<from>KTS</from><to>KV</to>
<status>1</status><dir>345</dir>
</item>
...
</channel>
</rss>
http://www.apps4finland.fi/fi/data/junat-kartalla-palvelun-rajapinta/
Workshop on Open Location Data 2011 Finnish Geodetic Institute 5
janne.kovanen@fgi.fi

6. Demo 1: Static one time feed
// Use some proxy. Add the IP address to the proxy file before this
OpenLayers.ProxyHost = “/cgi-bin/proxy.cgi?url=”;
// Initialize OpenLayers
function init() {
var map = new OpenLayers.Map('map');
// Create the background map layers etc (the other demo)
// Create the train layer
var newTrainLayer = new OpenLayers.Layer.GeoRSS(
“Train Feed”,
“http://188.117.35.14/TrainRSS/TrainService.svc/AllTrains”,
{projection: new OpenLayers.Projection(“EPSG:4326”)});
map.addLayer(newTrainLayer);
// Add controls etc.
}
Workshop on Open Location Data 2011 Finnish Geodetic Institute 6
janne.kovanen@fgi.fi

7. “Trains on a map” interface
Detailed information on trains
<rss version="2.0”>
<channel xmlns:georss="http://www.georss.org/georss">
<title>P 704</title>
<description>Train information feed for train P 704</description>
<lastBuildDate>Fri, 16 Sep 2011 13:57:05 +0300</lastBuildDate>
<category>1</category>
<georss:point>62.2989900000001 27.1673200000001</georss:point>
<speed>33</speed>
<heading>355</heading>
<startStation>OL</startStation>
<endStation>KUO</endStation>
<status>1</status>
<reasonCode/>
<lateness>0</lateness>
…
</channel>
</rss>
Workshop on Open Location Data 2011 Finnish Geodetic Institute 7
janne.kovanen@fgi.fi

8. “Trains on a map” interface
Detailed information on trains
<rss version="2.0”>
<channel xmlns:georss="http://www.georss.org/georss">
<title>P 704</title>
<description>Train information feed for train P 704</description>
<lastBuildDate>Fri, 16 Sep 2011 13:57:05 +0300</lastBuildDate>
<category>1</category>
<georss:point>62.2989900000001 27.1673200000001</georss:point>
<speed>33</speed>
<heading>355</heading>
<startStation>OL</startStation>
<endStation>KUO</endStation>
<status>1</status>
<reasonCode/>
<lateness>0</lateness>
…
</channel>
</rss>
Workshop on Open Location Data 2011 Finnish Geodetic Institute 8
janne.kovanen@fgi.fi

9. “Trains on a map” interface
Detailed information on trains
<rss version="2.0"><channel xmlns:georss="http://www.georss.org/georss"><title>IC 71</title><description>Train information feed for train IC 71</description><lastBuildDate>Mon, 19 Sep 2011 11:41:47 +0300</
lastBuildDate><category>1</category><georss:point>62.2989900000001 27.1673200000001</georss:point><speed>33</speed><heading>355</heading><startStation>HKI</startStation><endStation>KAJ</endStation><status>1</
status><reasonCode> </reasonCode><lateness>0</lateness><item><guid isPermaLink="false">HKI</guid><title>HKI</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime/
><scheduledDepartTime>08:12</scheduledDepartTime><eta/><etd>08:12</etd><stationCode>HKI</stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid
isPermaLink="false">PSL</guid><title>PSL</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>08:17</scheduledTime><scheduledDepartTime>08:18</
scheduledDepartTime><eta>08:17</eta><etd>08:18</etd><stationCode>PSL</stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">TKL</
guid><title>TKL</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>08:27</scheduledTime><scheduledDepartTime>08:28</scheduledDepartTime><eta>08:27</
eta><etd>08:28</etd><stationCode>TKL</stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">LH</guid><title>LH</title><description>Summary</
description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>09:06</scheduledTime><scheduledDepartTime>09:08</scheduledDepartTime><eta>09:06</eta><etd>09:08</etd><stationCode>LH</
stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">KV</guid><title>KV</title><description>Summary</description><pubDate>Mon, 19 Sep 2011
11:41:47 +0300</pubDate><scheduledTime>09:38</scheduledTime><scheduledDepartTime>09:52</scheduledDepartTime><eta>09:38</eta><etd>09:52</etd><stationCode>KV</stationCode><completed>1</completed><status>5</
status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">MR</guid><title>MR</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>10:30</
scheduledTime><scheduledDepartTime>10:31</scheduledDepartTime><eta>10:30</eta><etd>10:31</etd><stationCode>MR</stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></
item><item><guid isPermaLink="false">MI</guid><title>MI</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>10:55</scheduledTime><scheduledDepartTime>10:58</
scheduledDepartTime><eta>10:55</eta><etd>10:58</etd><stationCode>MI</stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">HAU</
guid><title>HAU</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>11:21</scheduledTime><scheduledDepartTime>11:22</scheduledDepartTime><eta>11:21</
eta><etd>11:22</etd><stationCode>HAU</stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">PM</guid><title>PM</title><description>Summary</
description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>11:41</scheduledTime><scheduledDepartTime>11:46</scheduledDepartTime><eta>11:41</eta><etd>11:46</etd><stationCode>PM</
stationCode><completed>0</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">SNJ</guid><title>SNJ</title><description>Summary</description><pubDate>Mon, 19 Sep 2011
11:41:47 +0300</pubDate><scheduledTime>12:14</scheduledTime><scheduledDepartTime>12:15</scheduledDepartTime><eta>12:14</eta><etd>12:15</etd><stationCode>SNJ</stationCode><completed>0</completed><status>5</
…
>09:06</scheduledTime><scheduledDepartTime>09:08</scheduledDepartTime><eta>09:06</eta><etd>09:08</etd><stationCode>LH</stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></
item><item><guid isPermaLink="false">KV</guid><title>KV</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>09:38</scheduledTime><scheduledDepartTime>09:52</
scheduledDepartTime><eta>09:38</eta><etd>09:52</etd><stationCode>KV</stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">MR</
guid><title>MR</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>10:30</scheduledTime><scheduledDepartTime>10:31</scheduledDepartTime><eta>10:30</
eta><etd>10:31</etd><stationCode>MR</stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">MI</guid><title>MI</title><description>Summary</
description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>10:55</scheduledTime><scheduledDepartTime>10:58</scheduledDepartTime><eta>10:55</eta><etd>10:58</etd><stationCode>MI</
stationCode><completed>1</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">HAU</guid><title>HAU</title><description>Summary</description><pubDate>Mon, 19 Sep 2011
11:41:47 +0300</pubDate><scheduledTime>11:21</scheduledTime><scheduledDepartTime>11:22</scheduledDepartTime><eta>11:21</eta><etd>11:22</etd><stationCode>HAU</stationCode><completed>1</completed><status>5</
status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">PM</guid><title>PM</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>11:41</
scheduledTime><scheduledDepartTime>11:46</scheduledDepartTime><eta>11:41</eta><etd>11:46</etd><stationCode>PM</stationCode><completed>0</completed><status>5</status><georss:point>0 0</georss:point></
item><item><guid isPermaLink="false">SNJ</guid><title>SNJ</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>12:14</scheduledTime><scheduledDepartTime>12:15</
scheduledDepartTime><eta>12:14</eta><etd>12:15</etd><stationCode>SNJ</stationCode><completed>0</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">KUO</
guid><title>KUO</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>12:43</scheduledTime><scheduledDepartTime>12:47</scheduledDepartTime><eta>12:43</
eta><etd>12:47</etd><stationCode>KUO</stationCode><completed>0</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">SIJ</guid><title>SIJ</title><description>Summary</
description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>13:05</scheduledTime><scheduledDepartTime>13:06</scheduledDepartTime><eta>13:05</eta><etd>13:06</etd><stationCode>SIJ</
stationCode><completed>0</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">LNA</guid><title>LNA</title><description>Summary</description><pubDate>Mon, 19 Sep 2011
11:41:47 +0300</pubDate><scheduledTime>13:32</scheduledTime><scheduledDepartTime>13:33</scheduledDepartTime><eta>13:32</eta><etd>13:33</etd><stationCode>LNA</stationCode><completed>0</completed><status>5</
status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">ILM</guid><title>ILM</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>13:48</
scheduledTime><scheduledDepartTime>13:50</scheduledDepartTime><eta>13:48</eta><etd>13:50</etd><stationCode>ILM</stationCode><completed>0</completed><status>5</status><georss:point>0 0</georss:point></
item><item><guid isPermaLink="false">SKV</guid><title>SKV</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>14:13</scheduledTime><scheduledDepartTime>14:14</
scheduledDepartTime><eta>14:13</eta><etd>14:14</etd><stationCode>SKV</stationCode><completed>0</completed><status>5</status><georss:point>0 0</georss:point></item><item><guid isPermaLink="false">KAJ</
guid><title>KAJ</title><description>Summary</description><pubDate>Mon, 19 Sep 2011 11:41:47 +0300</pubDate><scheduledTime>14:40</scheduledTime><scheduledDepartTime/><eta>14:40</eta><etd/><stationCode>KAJ</
stationCode><completed>0</completed><status>5</status><georss:point>0 0</georss:point></item></channel></rss>
Workshop on Open Location Data 2011 Finnish Geodetic Institute 9
janne.kovanen@fgi.fi

10. Demo 2: Make the trains move
// Add the trains layer in the init() through a function call
function init() {
// …
updateTrains();
}
function updateTrains() {
// Do not yet show the trains layer in the layer switcher
var newTrainLayer = new OpenLayers.Layer.GeoRSS(
“Train Feed”,
“http://188.117.35.14/TrainRSS/TrainService.svc/AllTrains”,
{projection: new OpenLayers.Projection(“EPSG:4326”),
displayInLayerSwitcher: false});
map.addLayer(newTrainLayer);
// Add a listener for loading
newTrainLayer.events.register("loadend", self,
function(e) {trainsLoaded(e)});
}
Workshop on Open Location Data 2011 Finnish Geodetic Institute 10
janne.kovanen@fgi.fi

11. … Demo 2: Make the trains move
// The update interval in milliseconds
var trainSetUpdateTimeout = 2000;
function trainsLoaded(event) {
if(event.object == null)
return;
if(trainsLayer != null && trainsLayer != event.object) {
map.removeLayer(trainsLayer, false);
}
trainsLayer = event.object;
// Now show the trains layer on the map and in the layer switcher
trainsLayer.setVisibility(true);
trainsLayer.displayInLayerSwitcher = true;
// Timed update
self.setTimeout('updateTrains()', trainSetUpdateTimeout);
}
Example 2
Workshop on Open Location Data 2011 Finnish Geodetic Institute 11
janne.kovanen@fgi.fi

12. Demo 3: Extending OpenLayers
var TrainRSS = OpenLayers.Class(OpenLayers.Format.XML, {
initialize: function(options) {
OpenLayers.Format.XML.prototype.initialize.apply(this, [options]);
},
…
}
var TrainFeature = OpenLayers.Class(OpenLayers.Feature, {
guid: "”, type: 0, speed: 0, heading: 0, status: 0,
initialize: function(layer, lonlat, data) {
OpenLayers.Feature.prototype.initialize.apply(this, [layer, lonlat, data]);
},
…
}
Workshop on Open Location Data 2011 Finnish Geodetic Institute 12
janne.kovanen@fgi.fi

13. … Demo 3: Extending OpenLayers
var TrainsRSS = OpenLayers.Class(OpenLayers.Format.GeoRSS, {
layer: null,
initialize: function(layer, options) {
OpenLayers.Format.GeoRSS.prototype.initialize.apply(this, [options]);
this.layer = layer;
},
…
},
var TrainsLayer = OpenLayers.Class(OpenLayers.Layer.GeoRSS, {
initialize: function(name, location, options) {
OpenLayers.Layer.GeoRSS.prototype.initialize.apply(this,
[name, location, options]);
},
…
},
Workshop on Open Location Data 2011 Finnish Geodetic Institute 13
janne.kovanen@fgi.fi

14. “Trains on a map” interface
Train station information
<rss version="2.0">
<channel xmlns:georss="http://www.georss.org/georss">
<title />
<description>Station information feed for station KML</description>
<lastBuildDate>Thu, 03 Feb 2011 17:18:42 +0200</lastBuildDate>
<category>Train System</category>
<item>
<guid isPermaLink="false">P274</guid>
<category>1</category>
<title>P 274</title>
<description>Summary</description>
<pubDate>Thu, 03 Feb 2011 17:18:42 +0200</pubDate>
<georss:point>0 0</georss:point>
…
</item>
…
</channel>
</rss>
http://www.apps4finland.fi/fi/data/junat-kartalla-palvelun-rajapinta/
Workshop on Open Location Data 2011 Finnish Geodetic Institute 14
janne.kovanen@fgi.fi