Hi Karoli. I’ve been developing something related to what your talking about, for RoboCal. In my case, I’ve been doing it to support what I call RoboTweets, which are audio tweets that get plotted on a map.
If I understand what you’re trying to do, I think I can adapt my system. The idea is to send a direct message to the Twitter user “robocalinfo”. This message is then sent to the Google geocoding software to come up with a latitude and longitude to plot on a map.
The cool thing is, Google Maps is good at processing input in various forms. Thus, the following direct messages will result in a lat and longitude being determined:
D robocalinfo New York, New York
D robocalinfo 200 Lincoln Avenue, Portsmouth, NH
In the case of my RoboTwitter tool, I attach an audio message to the plotted location. But if you just want to find out where people are, the same idea can be used.
Let me know if you’re interested.
Thanks,
Ted Gilchrist

