I've been spending a lot of time learning chinese, and have some ideas for apps that would make this complicated process easier.
I'm looking for datasets (ideally free) that I can use to back an app I want to write.
The dataset should have definitions, character ranks, frequency data, radical composition data etc.
An example of an existing app is http://www.hanzicraft.com/character/%E5%AE%89
Where does one obtain such data?