Is it possible to use Google Chart offline ?
According to their API lisense, you are not authorized to download google jsapi and google visualization.
However, you can find some solutions on Github.
For example, if you search : “GChart offline example” on Google.
But you should now that you will probably blacklisted on Google if you use that kind of scripts on your websites.
And also, it is very limited, and buggy. You can’t align the charts, the charts will eat the texts under it, etc…