When plotting data, check each value against the measurement calibrations and apply the sloped and offset

[kevinworthington]

Each measure can have one or more calibrations. These have a start date, a slope and an offset.
An end-time is assumed base on the addition of a new calibration.
If the measurement value falls within a calibration's start and end time apply it.
If no slope of offset, use slope =1, and offset=0