James:

Still a few things I have to apologize for when showing the app.
1. No landscape view
2. Cannot resume from a pause (resets)
3. Scaling is crazy

If you would like an example of a beautiful graphing app….

Any of the audio apps by Andrew Smith (Studio Six Digital)

He gives the option to set the range of the scale and either zero or zoom to a range.

Gives you a sliding bar to give the exact value at the intersection point.

It is a genuine pleasure to use.