Field parameters
A Field Parameter is an in-situ measurement you take with a probe in the field — such as pH, dissolved oxygen (DO), oxidation-reduction potential (ORP), specific conductance, temperature, or turbidity. You record these readings in a session: a single field-measurement event at a Location within a Site. A session groups time-ordered readings, and each reading holds one measurement per parameter, so the values you cast over the course of a purge or a profile stay together as one record.
The three levels of a session
A field-parameter record is a three-level structure: a Session contains Readings, and each Reading contains Measurements.
- A Session is the measurement event. It carries the Location, the owning Project, an optional Well, a start time, an optional end time, and session-level stabilization tracking.
- A Reading is one cast or time point within the session. It carries a timestamp and, optionally, the probe depth in the water column.
- A Measurement is one parameter value within a reading — a
(Parameter, Value + Unit)pair. A reading holds many measurements, one per parameter.
Figure: a Field Parameter session nests Readings, and each Reading nests one Measurement per parameter.
Measurement pairs
Each measurement is a parameter paired with a value and a unit. The Parameter (for example pH or Dissolved Oxygen) and the Unit are both reference data — you pick them from the managed lists rather than typing free text. The value is signed, because parameters like pH, ORP, and dissolved oxygen can read zero or below.
A reading holds one measurement per parameter — you cannot record the same parameter twice in the same reading. To capture a parameter again over time, add another reading to the session.
How a session is scoped
A session belongs to a Site and a Project — the same scope as the site's water levels, well purges, and logger streams. The Location is a field on the session, not the scope it lives under. In practice you still create and view sessions from a specific Location's tab, but the record is owned and queried at the Site level, alongside the site's other field-monitoring records.
A session does not store a link to a Well Purge or a Sample. During low-flow sampling these readings are the purge stabilization signal, but Erde correlates them by Location and time rather than by a stored reference, so each record stays independent.
How it fits together
Field parameters are one of four field-monitoring record types, all attached to a Location within a Site. They differ in what they capture and in how deeply they nest.
| Aspect | Field parameters | Water levels / well purges | Logger streams |
|---|---|---|---|
| What it records | In-situ probe readings (pH, DO, ORP, etc.) | A single gauging or purge event | High-frequency time series from a continuous logger |
| Structure | Session → Reading → Measurement | One flat record per event | Stream → Channel → Reading |
| Measurement values | One per parameter, per reading | Fixed fields on the record | One channel per parameter; many timestamped readings per channel |
| Scope | Site and Project | Site and Project | Site and Project |
Both the Parameter and the Unit on a measurement come from reference data, managed under administration. Sessions, readings, and measurements are stored as one aggregate, so Erde saves, locks, and audits them as a unit.
Delete several measurements at once
A reading's Measurements grid supports multi-select deletion. Tick the checkbox on each row you want (or the header checkbox to select the whole page), then select Delete selected (N) above the grid and confirm.
Bulk deletion is permanent and cannot be undone. Each removed measurement is recorded individually in the Audit Log. Bulk delete is unavailable while the Site is locked.
Related
- Record monitoring data — the end-to-end task of adding and editing field records.
- Water levels, well purges, and continuous loggers — the other three field-monitoring record types.
- Reference data — where Parameters and Units are managed.