Lonely Planet Developer Network Developer Blog

To get you started, we thought we should share a little bit about http://m.lonelyplanet.com , our mobile site that provides the Lonely Planet community with always-on real-time access to our content. The attached zip / tar contains an example page from the mobile site as well as a php shell for all the standard Explore API calls. [zip | tar]

What excites us about mobile is that it enables us to make our services available anywhere, anytime and provide answers to a new set of questions like "what should I explore today?" and "what's around me that's worth experiencing?".

As part of their extensive on the ground research, our authors filter and review tens of thousands of points of interest (POI's), such as restaurants, hotels, bars, shops and sights. They also plot the position of these POI's on the maps that form part of our guidebooks, so we have accurate, collected geocodes corresponding with each POI. So, we built a mobile site that is really a mash-up of this location-aware Lonely Planet content through using our Explore API webservices and some of the Google geo API's.

To answer the question "what's around me?" we have to have a sense of where the user is in order to work out what content we have that would be contextually relevant to them. As this is a browser-based service, we don't have the luxury of location API's to tap into to get your precise location via GPS or cell tower triangulation.

For the most accurate results, we needed the users to self select their location by entering it into a form field. Because typing on regular mobile keypad is so laborious, we wanted to keep that to a minimum and offload the geo-parsing to a powerful server-side geocoder which could deal with the ambiguity of short location descriptions, various zip/post code formats etc. For this we use the Google Geocoder API. This API enables users to enter any kind of location description from zip codes (90210) to tube stations (holborn) to street names (oxford street) to suburbs (footscray) and the geocoder will either decipher that and return the lat/long of that location or it will provide multiple results back for disambiguation.

Now that we know the user's location (lat/long), we can assess what content we have available that may be relevant to them. Using our POI Proximity webservice, we pass in the user's location and a radius in kilometers to calculate what POI's we have nearby. The POI Proximity service returns a list of POI's with their relative distance from the user's location which we use to order the presentation of those results.

Now we need a way to present the user's location and the location of the nearby POI's on a map. Since this is an application for a baseline of devices with limited capabilities, we don't have the luxury of Flash, AJAX or any other form of client-side scripting such as JavaScript. For this we use the Static Maps API. By passing in the geocodes and parameters for labelling the markers, the Static Maps API produces for us a static image displaying markers which correspond with the user's location and each of the POI's.

We use another fantastic open resource, called WURFL, to detect the user's mobile device type. We get from that database a range of device characteristics, including screen size and supported media types which we then use as paramters in the call to the Static Maps API to get a map with the appropriate width/height and file format (eg gif, jpg, png, etc). Users can further filter the results by selecting the type of POI they are interested in (eg eat, sleep, see, play, etc).

This is our first effort at a location based service so there is still much to do to improve and enhance the mobile site. To see it in action, go to http://m.lonelyplanet.com in your mobile browser, select the "What's around me?" feature and enter your location or a place you're planning to travel to in order to see the nearby POI's, recommended and reviewed by our authors, displayed on a map relative to your location.