OUseful.Info, the blog…

Trying to find useful things to do with emerging technologies in open education

Discovering Co-location Communities – Twitter Maps of Tweets Near Wherever…

As privacy erodes further and further, and more and more people start to reveal where they using location services, how easy is it to identify communities based on location, say, or postcode, rather than hashtag? That is, how easy is it to find people who are colocated in space, rather than topic, as in the hashtag communities? Very easy, it turns out…

One of the things I’ve been playing with lately is “community detection”, particularly in the context of people who are using a particular hashtag on Twitter. The recipe in that case runs something along the lines of: find a list of twitter user names for people using a particular hashtag, then grab their Twitter friends lists and look to see what community structures result (e.g. look for clusters within the different twitterers). The first part of that recipe is key, and generalisable: find a list of twitter user names

So, can we create a list of names based on co-location? Yep – easy: Twitter search offers a “near:” search limit that lets you search in the vicinity of a location.

Here’s a Yahoo Pipe to demonstrate the concept – Twitter hyperlocal search with map output:

Pipework for twitter hyperlocal search with map output

[UPDATE: since grabbing that screenshot, I’ve tweaked the pipe to make it a little more robust…]

And here’s the result:

Twitter local trend

It’s easy enough to generate a widget of the result – just click on the Get as Badge link to get the embeddable widget code, or add the widget direct to a dashboard such as iGoogle:

Yahoo pipes map badge

(Note that this pipe also sets the scene for a possible demo of a “live pipe”, e.g. one that subscribes to searches via pubsubhubbub, so that whenever a new tweet appears it’s pushed to the pipe, and that makes the output live, for example by using a webhook.)

You can also grab the KML output of the pipe using a URL of the form:
http://pipes.yahoo.com/pipes/pipe.run?_id=f21fb52dc7deb31f5fffc400c780c38d&_render=kml&distance=1&location=YOUR+LOCATION+STRING
and post it into a Google maps search box… like this:

Yahoo pipe in google map

(If you try to refresh the Google map, it may suffer from result cacheing.. in which case you have to cache bust, e.g. by changing the distance value in the pipe URL to 1.0, 1.00, etc…;-)

Something else that could be useful for community detection is to search through the localised/co-located tweets for popular hashtags. Whilst we could probably do this in a separate pipe (left as an exercise for the reader), maybe by using a regular expression to extract hashtags and then the unique block filtering on hashtags to count the reoccurrences, here’s a Python recipe:

import simplejson, urllib

def getYahooAppID():
  appid='YOUR_YAHOO_APP_ID_HERE'
  return appid

def placemakerGeocodeLatLon(address):
  encaddress=urllib.quote_plus(address)
  appid=getYahooAppID()
  url='http://where.yahooapis.com/geocode?location='+encaddress+'&flags=J&appid='+appid
  data = simplejson.load(urllib.urlopen(url))
  if data['ResultSet']['Found']>0:
    for details in data['ResultSet']['Results']:
      return details['latitude'],details['longitude']
  else:
    return False,False

def twSearchNear(tweeters,tags,num,place='mk7 6aa,uk',term='',dist=1):
  t=int(num/100)
  page=1
  lat,lon=placemakerGeocodeLatLon(place)
  while page<=t:
    url='http://search.twitter.com/search.json?geocode='+str(lat)+'%2C'+str(lon)+'%2C'+str(1.0*dist)+'km&rpp=100&page='+str(page)+'&q=+within%3A'+str(dist)+'km'
    if term!='':
      url+='+'+urllib.quote_plus(term)

    page+=1
    data = simplejson.load(urllib.urlopen(url))
    for i in data['results']:
     if not i['text'].startswith('RT @'):
      u=i['from_user'].strip()
      if u in tweeters:
        tweeters[u]['count']+=1
      else:
        tweeters[u]={}
        tweeters[u]['count']=1
      ttags=re.findall("#([a-z0-9]+)", i['text'], re.I)
      for tag in ttags:
        if tag not in tags:
    	  tags[tag]=1
    	else:
    	  tags[tag]+=1
    	    
  return tweeters,tags

''' Usage:
tweeters={}
tags={}
num=100 #number of search results, best as a multiple of 100 up to max 1500
location='PLACE YOU WANT TO SEARCH AROUND'
term='OPTIONAL SEARCH TERM TO NARROW DOWN SEARCH RESULTS'
tweeters,tags=twSearchNear(tweeters,tags,num,location,searchTerm)
'''

What this code does is:
– use Yahoo placemaker to geocode the address provided;
– search in the vicinity of that area (note to self: allow additional distance parameter to be set; currently 1.0 km)
– identify the unique twitterers, as well as counting the number of times they tweeted in the search results;
– identify the unique tags, as well as counting the number of times they appeared in the search results.

Here’s an example output for a search around “Bath University, UK”:

Having got the list of Twitterers (as discovered by a location based search), we can then look at their social connections as in the hashtag community visualisations:

Community detected around Bath U.. Hmm,,, people there who shouldnlt be?!

And wondering why the likes @pstainthorp and @martin_hamilton appear to be in Bath? Is the location search broken, picking up stale data, or some other error….? Or is there maybe a UKOLN event on today I wonder..?

PS Looking at a search near “University of Bath” in the web based Twitter search, it seems that: a) there arenlt many recent hits; b) the search results pull up tweets going back in time…

Which suggests to me:
1) the code really should have a time window to filter the tweets by time, e.g. excluding tweets that are more than a day or even an hour old; (it would be so nice if Twitter search API offered a since_time: limit, although I guess it does offer since_id, and the web search does offer since: and until: limits that work on date, and that could be included in the pipe…)
2) where there aren’t a lot of current tweets at a location, we can get a profile of that location based on people who passed through it over a period of time?

UPDATE: Problem solved…

The location search is picking up tweets like this:

Twitter locations...

but when you click on the actual tweet link, it’s something different – a retweet:

Twitter reweets pass through the original location

So “official” Twitter retweets appear to pass through the location data of the original tweet, rather than the person retweeting… so I guess my script needs to identify official twitter retweets and dump them…

PS if you want to see how folk tweeting around a location are socially connected (i.e. whether they follow each other), check out A Bit of NewsJam MoJo – SocialGeo Twitter Map).

Written by Tony Hirst

October 27, 2010 at 1:15 pm

8 Responses

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  1. […] Médias locaux // Visualiser une communauté géolocalisée avec Twitter et Yahoo Pipes (OUseful.Inf… Tutorial de Tony Hirst pour identifier une communauté locale et la projeter sur une carte. (tags: twitter yahoo pipes communauté geolocatisation webjournalisme) […]

  2. […] Discovering co-location communities. Fascinating bit of arch-geekery. This clever bit of programming allows you to find out what people are saying on Twitter in an area of your choice. Could be a brilliant (or terrifying) tool for councillors to help them stay in touch with their ward. We’ll be having a dig into this. […]

  3. […] for example, my ‘find folk tweeting near a location’ hack uses the Twitter search API to construct a geofenced locale and then search for tweets within […]

    OUseful.Info, the blog…

    November 25, 2010 at 11:48 am

  4. […] couple of pre-existing tools/components: a geo-based Twitter search constructed using Yahoo Pipes (Discovering Co-location Communities – Twitter Maps of Tweets Near Wherever…); and a map of social network connections between folk recently using a particular search term or […]

  5. […] doesn’t have to be a list, it might be a list of names of folk using a particular hashtag, or tweeting from a particular location, or even just the folk followed by a particular individual, for example); in the case of UK HEIs, […]

  6. […] a map showing tweets generated from postcode areas in London during the riots”. A post on the OUseful blog explains exactly how this is […]

  7. […] Discovering Co-location Communities – Twitter Maps of Tweets Near Wherever… […]

  8. […] search feeds (JSON, I think, though RSS used to be an alternative too?) for mapping tweets, or discovering colocation communities. Or a twitter to audio pipe; or a pipe for serendiptitously discovering content related to a […]


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