mappiness is a research project by the London School of Economics.
We're particularly interested in how people's happiness is affected by their local environment — air pollution, noise, green spaces, and so on — which the data from mappiness will be absolutely great for investigating.
We beep you once (or more) a day to ask how you're feeling, and a few basic things to control for: who you're with, where you are, what you're doing (if you're outdoors, you can also take a photo)
The data gets sent back — anonymously and securely — to our data store, along with your approximate location from the iPhone's GPS, and a noise-level measure
http://www.mappiness.org.uk/