How can I compress data that represents a number's change over time?
In the case of storage and querying from the storage i.e. if you can first get all time:value pairs, you can use curve fitting (regression) to get the polynomial function v=f(t), where v = value and t = time which will not be accurate, may even be outside 5% error margin; but would the  get the work done in a very low file size and acceptable(?) margin of error.