Elphin » Geodata

Geohash PHP class

admin — Thu, 28 Feb 2008 00:43:15 +0000

geohash.org popped up recently with a method of generating short hash codes for geographical locations. The codes have some interesting properties and the algorithm is documented on wikipedia.

I recently started doing a Project Euler problem a day as a fun diversion. I found the geohash algorithm intriguing, so it became my “Euler problem” for the day!

Having done it, I’m not sure I’ll find a use for it myself, but if anyone else finds it handy, do let me know!

Download it here.

Yahoo ZoneTag

admin — Wed, 11 Jul 2007 08:43:56 +0000

Now that I’ve got pastebin back on an even keel, there’s lots of Geograph work to be done. I’ve been slowly working on a tagging engine which is nearing completion, but this morning Barry Hunter pointed me in the direction of Yahoo’s ZoneTag project (via HighEarthOrbit)

ZoneTag can suggest your location and tagging information based on cellphone tower, zipcode or latitude & longitude. The last piece of the tagging system I’m working on is the suggestion engine, so this was of great interest.

I gave it a quick test run, and predictably, it’s a case of feast or famine. A request for my home town of Baldock in the UK produces two results – “Plinston Hall” and “Letchworth” – so not entirely useful. More fruitful was a request for the location of the London Eye – you’re deluged with a plethora of data – here are the “venue” tags it suggests:

Waterloo, cleopatra’s needle, Eurostar, Downing Street, Eagle, London Eye, Guard, Waterloo Station, Parliament, Somerset House, Whitehall, Westminster, Memorial, skyline, Big Ben, Embankment, Thames, graffiti, Hungerford Bridge, Dali, SW1, horse, Eye, Banksy, train, Trafalgar Square, National Theatre, St Martins Lane, trains, station, Ferris Wheel, bridge, river, Guards, church, SE1, pub, Waterloo Bridge, Protest, IMAX, Horse Guards Parade, Wheel, River Thames, Charing Cross, Underground, View, sign, Southwark, House, Tube, Palace of Westminster, Horse Guards, Red, night, London Aquarium, Victoria Tower, england, sky, UK, Lion, long exposure, blue, statue, Trafalgar, Lambeth, Millenium Wheel, Demonstration, Peace, Anti War, Bus, Elephant, Europe, Clock, Nelsons Column, Street, Oxo Tower, Guess Where London

Perhaps a few too many there, but still, not a bad result. As it’s an experimental beta, not sure we can use it directly for Geograph, but it might serve as a useful comparison for our own suggestion engine. We could even offer a compatible service based on our own data too…

PhotoSynth

admin — Thu, 07 Jun 2007 20:08:51 +0000

I’ve heard about PhotoSynth, Microsoft’s rather cool technology for placing photos within a 3D space, but this Photosynth demo by its architect Blaise Aguera y Arcas is truly impressive – listen to the gasps from the audience as the penny drops on what they are seeing.

I’d love to throw it at some Geograph squares – some of the more touristy squares have oodles of PhotoSynth fodder.

Geolocated Wikipedia articles in Google Earth

admin — Thu, 26 Oct 2006 13:28:36 +0000

Here’s a neat idea – a Google Earth KML file of geolocated wikipedia articles. As you roam the Earth, see links to relevant articles popup. Might be even better as a dynamic link, so that Google Earth simply requests articles for the field of view, then it could stay updated, but still, a nice concept!