Geofenced Audio Tours and Geo-Privacy

Whilst on holiday a couple of weeks ago, we took an audio tour on an open top bus. I missed a significant chunk of the tour because my headphones broke after the first couple of minutes (the cable was only a tiny, easily snapped strand of copper thick… I guess the cost of copper played a part in that…?!) but it got me thinking (again) about geofenced audio tours.

If the term is new to you, geofencing refers to a technique where you put a notional boundary round a location and capture the GPS coordinates of the boundary; if the boundary is a regular shape, you can calculate the boundary co-ordinates via a simple formula. For example, if you have a circular region 1 km wide about a point, the geofence is defined by the circumference (or as Terry Pratchett would say,m the circumfence) of the circle, centred on the point of interest and with a radius of 0.5km. The geofenced region then lies within this circle.

For audio tours, what this means is that you can go for a walk, or a ride, and as an when you within the confines of the geofence around an object, a commentary about that object can play out for you. I had a quick look around for apps that might support the creation of such a tour, but there didn’t seem to be much out there. Here’s what I did find though:

Hackney Hear – An interactive GPS-triggered audio tour of Hackney; creative arts project to develop an audio tour app around the London Borough of Hackney; due out in January 2012. Looks exciting (will they open the code, I wonder?)
NoTours – Augmented Aurality for Android: this site includes an editor for creating your own geofenced audio tours, and a demo app that lets you play a tour with up to 10(?) audio locations marked. The site espouses open source principles but I couldn’t see a link to the code anywhere? (The site name actually reminded me of the idea of a misguided walk;-)
Geovative geotours: a commercial offering, though the free plan suggests you can create up to three tours.

Unfortunately, I’ve not had a chance to play with any of them yet…

(If you know of any others, particularly open source apps and tour creators, please let me know via the comments.)

One thing I’d quite like to do one day is create an app that I can listen to on the motorway that will play out stories about the places I’m passing. (I wonder if I could build such a thing in Android App inventor?). As a first pass, I could imagine querying something like Wikipedia (e.g. using this new wikilocation api) to pull back articles relating to points of interest near my current location, and then using text to speech to read a selected article out.

(Note to self: I think Audioboo allows geotagged audio uploads. Does it also support geo-based searches? This could provide a secondary source of commentaries…?)

It might also be fun to try to create tours for bus routes, e.g. as identified from the wonderful new MySociety site, FixMyTransport (though adding such functionality to that site directly would be the sort of feature creep that I think MySociety sites always try to avoid: How to create sustainable open data projects with purpose).

And finally, whilst on the question of geofences, and what actually brought them back to mind today: flickr has just opened up geo-privacy fences: Introducing geofences on Flickr!:

Geofences are special locations that deserve their own geo privacy settings. For example, you might want to create a geofence around the your “home” or “school” that only allows “Friends and Family” to see the location of the photos you geotag in that area. So the next time you upload a photo with a geotag in the radius of a geofence, it will follow the default geo privacy you’ve designated for that hotspot.

Clever ;-)

PS here’s an alternative take on “geofences” (h/t @AidanBaker for the reminder about this art piece:-)

The artists involved created a rod that showed the wifi strength at a particular location, then, using time lapsed photography, took it for a walk: Immaterials: Light painting WiFi

PPS fwiw, you can run spatial queries over geo-data hosted in Google Fusion Tables: Search your geo data using spatial queries from Fusion Tables Spatial queries can be run “via the WHERE clause. The syntax is: ST_INTERSECTS(, ) For , use a in your table that contains location data. For , use one of the following: ” I haven’t tried it yet, but this approach looks amenable to geofence style query activity within regularly bounded regions.
A weaker spatial query form (that cannot be combined with ST_INTERSECTS conditions) to use ORDER BY based on distance. “The syntax is: ST_DISTANCE(, ) For , use a in your table that contains location data. Listing the as a is optional when using ORDER BY ST_DISTANCE. ORDER BY ST_DISTANCE cannot be combined with any of the ST_INTERSECTS conditions.”

PPPS and finally, just in case, here’s a link to the code repository for the Google MyTracks Android app; it may contain useful code snippets for any homebrew native Android app…