Can generate charts such as histograms, graphs, pie charts, and so on data. Charges or free are available, preferably open source.
There's a good recommendation.
There's a jfree, which can be used to do the server.If you don't mind, you can use raphaeljs.com or highcharts.
Open source free:
Now there's an open source objc wrapper for ios/os x, which is free to use.