Back in 2008, when I worked for Yahoo!, I had the good fortune of chatting with Tom Coates a few times about the now defunct Fire Eagle location brokerage service. Fire Eagle was my absolute favorite product to come out of Yahoo! during my time there. I've always been fascinated by real-time location data and sad that Fire Eagle's intersection of privacy and ease of use never caught on.
Anyway, fast-forward to last Summer, I was bummed that although so much of my life is documented through photos, tweets, and journal entries, my location data was missing. A few products tried to solve this problem post-Fire Eagle. Google Latitude (née Dodgeball) gave you a way to seamlessly track your location and view your history, but they've since sunsetted that product. And, besides, it was a little creepy having Google track your every step. (Which I realize they still are via Google Now, but that's another conversation.) There was also other apps like Rove and Foursquare, but none of them offered quite the feature set I was looking for. In 2010, I even went so far as to reverse engineer Apple's Find My iPhone API so I could remotely query my phone's location. That worked great, but doing so on a regular basis killed my battery life. But, with iOS 7's advances in background location reporting, I knew there had to be a better way. I wanted something that would automatically track my location as precisely as possible, respect my phone's battery life, keep that data private by default, yet still offer the ability to granularly share my location as I saw fit.
So I did what I always seem to do. I built my own app. It's called Rockwell, and it's available on GitHub.
Rockwell consists of two components. An iPhone app that monitors your location and allows you to annotate where you are using Foursquare's database of named locations. And a PHP/MySQL web service you can install on your own server that the app talks to.
As you go about your day, the iPhone app uses iOS' significant location change reporting feature to ping the web app with your location. The web app stores your location history and allows you to go back and search your history either by date or by location.
Further, since the website knows your most recent (current) location, you're able to share that with others. In my opinion, one of the reasons Fire Eagle failed was it was (by design) very difficult to get location data out of the service. You had to go through an intricate OAuth dance each time.
With Rockwell, you simply choose the location level you're comfortable sharing - either precise lat/lng coordinates, current city, current state, etc - and a format - plain text or JSON - and Rockwell generates a short url you can pass around. You can use that URL to embed your plain text location on your blog, or you can use the JSON version to do something more API-ish with it. There's no OAuth shenanigans to deal with. You can have as many short geo-links as you want, and each one can be revoked at any time.
One more thing I'd like to explain. The iPhone app reports two types of check-in data to the web service. The first kind is dumb. Just your latitude, longitude, and timestamp. Many apps like Rove and Foursquare use this data to try and generate automatic location check-ins. Based on your past history, your friends' location, and your location, they try and guess where you might actually be at a given time. Doing this well is the holy grail of location reporting. The problem is that I've yet to see any service get it right. In a dense urban area, with hundreds if not thousands of locations per square mile, there's just no reliable way to figure out where you really are with precision. (At least not without some serious machine learning, which I assume Foursquare is working on.) Rockwell dances around this problem by allowing you to augment your dumb check-ins with annotated ones. Just launch the app, tap "Check-in", and Rockwell pulls a list of nearby locations from Foursquare. Just tap on one and you're done. It's saved to the web service alongside the rest of your location history.
Rockwell is working great for me currently. All the basics work. The majority of the remaining work is around coming up with nice ways to show your location history in a useful way. The code is available on GitHub. I'd love it if you gave it a try, sent feedback, and maybe even a pull request or two.