Introduction to Geo hacking with (amongst others)

Yahoo Technology.

Chris&an Heilmann, Ignite, London, 2nd of March 2010

Geolocation is the new thing.

Good news is that it is not hard to do.

In the following half hour or so I will show you how to solve almost all Geo problems using YQL.

Using YQL in JavaScript:

There are a few different ingredients to playing with geo location.

Finding the current location.

Turning a location into a place.

Finding a geographical hierarchy.

Geo-tagging information.

Displaying geo information.

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Finding the current location happens in different ways.

The creepy way - IP sniffing.

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h;p://isithackday.com/hacks/geo/js‐loca&on.html

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The problem with IP sniffing is accuracy.

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The other problem: it is not reliable.

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The non-creepy and more accurate way - the W3C geolocation API.

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Firefox/(Mobile) Safari/Chrome (dev build)

Another way is of course to get location information from the user’s social presence.F

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Plazes, FireEagle, Twitter, Yahoo, Flickr, Foursquare, Gowalla, Brightkite, Google Buzz/Latitude, Dopplr...F

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Having a latitude and longitude is fine and dandy but it is ambiguous.

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The same lat/lon pair could be a lot of things - the centre of a town, a point of interest...

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This is why we need to turn lat/lon into something that is human readable.

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This is called reverse geocoding and there are a few services for it out there.

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My personal favourite (as it works world-wide) is the Flickr reverse geocoder.

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h;p://www.flickr.com/services/api/flickr.places.findByLatLon.html

You can use this using YQL:

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select * from flickr.places wherelat=51.5142271 and lon=‐0.1289602

To get more in-depth data, use flickr and Yahoo Geo:

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select * from geo.places where woeid in (  select place.woeid from flickr.places   where lat=51.5142271 and lon=‐0.1289602)

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Quick word on woeid: Use it. (Flickr, Dopplr, Twitter and Yahoo do)

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What’s around a certain location?

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h;p://developer.yahoo.com/geo/

GeoPlanet gives you hierarchies:

Parent, Ancestors, Children, Siblings, Neigbours, BelongTos.

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h;p://isithackday.com/geoplanet‐explorer/?woeid=615702

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h;p://isithackday.com/geoplanet‐explorer/geodrilldown.php

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Putting it all together, we can get this:

h;p://isithackday.com/hacks/geo/geotest.php

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What if you have no location but only a resource?

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h;p://developer.yahoo.com/geo/placemaker/Ge

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Placemaker takes a text, or a web URL and extracts the geographical information from it.

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. select * from geo.placemaker where documentContent = "Hey I am in Atlanta! I came here from London and will travel onwards to Las Vegas and Sao Paulo" and documentType="text/plain"

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. select * from geo.placemaker where documentURL ="h;p://icant.co.uk" and documentType="text/html" and appid=""

select * from geo.placemaker where documentURL ="h;p://newsrss.bbc.co.uk/rss/newsonline_uk_edi&on/front_page/rss.xml"and documentType="text/rss" and appid=""

Placemaker returns places and references - you can use these to enhance texts with geo information.

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To see Placemaker in action, check out the GeoMaker hack.

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h;p://github.com/codepo8/geomaker

h;p://icant.co.uk/geomaker/Ge

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Displaying geo information is done via Map APIs

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By far the easiest way to build a very simple map is to use the Google static maps API.

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<img src=”h;p://maps.google.com/maps/api/sta&cmap?sensor=false&size=200x200&maptype=roadmap&key=YOUR_MAP_KEY&markers=color:blue|label:1|37.4447,‐122.161&markers=color:blue|label:2|37.3385,‐121.886&markers=color:blue|label:3|37.3716,‐122.038&markers=color:blue|label:4|37.7792,‐122.42” alt=””>

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If you want to use Yahoo Maps with the data returned from the earlier YQL calls here’s the code:

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If you want to use any map provider easily without deep-diving into an API, use Mapstraction.

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h;p://www.mapstrac&on.com/

That’s it! You have the tools, now find a cause and get geo hacking!

h;p://delicious.com/tag/geotoys

  Chris&an Heilmann  h;p://wait‐&ll‐i.com   h;p://developer‐evangelism.com  h;p://twi;er.com/codepo8   

Cheers