 | Term | Definition |
 | Calibration Value | A value used as part of the calibration of an instrument at a particular time. |
| Derived Value | Data are the result of a mathematical transformation where there is some subjectivity in the selected equation form and/or where parameters are typically fitted. A rating curve relating stage to discharge is a transformation that fits this definition; therefore stage is observed but discharge is derived. |
| Estimated Value | Values that are roughly calculated, judged, or approximated. Values may result from professional judgement or from ancillary data. |
| Field Observation | Data reflect the measurement the sensor is designed to make, reported at the frequency of data collection |
| Model Simulation Result | Values generated by a simulation model |
| Sample | Observation that is the result of analyzing a sample in a laboratory |
| Unknown | The value type is unknown |
