# properties.id.description
A unique identifier representing a single collection series. This corresponds to the `field_measurement_series_id` field in the `field-measurements` endpoint. Collection series are defined as the set of field measurements at a given monitoring location for a single parameter code using a single reading type.

# properties.monitoring_location_id.description
A unique identifier representing a single monitoring location. This corresponds to the `id` field in the `monitoring-locations` endpoint. Monitoring location IDs are created by combining the agency code of the agency responsible for the monitoring location (e.g. USGS) with the ID number of the monitoring location (e.g. 02238500), separated by a hyphen (e.g. USGS-02238500).

# properties.parameter_code.description
Parameter codes are 5-digit codes used to identify the constituent measured and the units of measure. A complete list of parameter codes and associated groupings can be found at [https://api.waterdata.usgs.gov/ogcapi/v0/collections/parameter-codes/items](https://api.waterdata.usgs.gov/ogcapi/v0/collections/parameter-codes/items).

# properties.parameter_description.description
A description of what the parameter code represents, as used by WDFN and other USGS data dissemination products.

# properties.begin.title
Time series first observation timestamp - UTC

# properties.begin.description
The datetime of the earliest observation in the time series. Together with `end_utc`, this field represents the period of record of a time series. Note that some time series may have large gaps in their collection record.
You can query this field using date-times or intervals, adhering to RFC 3339, or using ISO 8601 duration objects. Intervals may be bounded or half-bounded (double-dots at start or end).
Examples:

  - A date-time: "2018-02-12T23:20:50Z"
  - A bounded interval: "2018-02-12T00:00:00Z/2018-03-18T12:31:12Z"
  - Half-bounded intervals: "2018-02-12T00:00:00Z/.." or "../2018-03-18T12:31:12Z"
  - Duration objects: "P1M" for data from the past month or "PT36H" for the last 36 hours

Only features that have a `begin_utc` that intersects the value of datetime are selected.

# properties.end.title
Time series most recent observation timestamp - UTC

# properties.end.description
The datetime of the most recent observation in the time series. Data returned by this endpoint updates at most once per day, and potentially less frequently than that, and as such there may be more recent observations within a time series than the time series `end_utc` value reflects. Together with `begin_utc`, this field represents the period of record of a time series. It is additionally used to determine whether a time series is "active".
You can query this field using date-times or intervals, adhering to RFC 3339, or using ISO 8601 duration objects. Intervals may be bounded or half-bounded (double-dots at start or end).
Examples:

  - A date-time: "2018-02-12T23:20:50Z"
  - A bounded interval: "2018-02-12T00:00:00Z/2018-03-18T12:31:12Z"
  - Half-bounded intervals: "2018-02-12T00:00:00Z/.." or "../2018-03-18T12:31:12Z"
  - Duration objects: "P1M" for data from the past month or "PT36H" for the last 36 hours

Only features that have a `end_utc` that intersects the value of datetime are selected.

# properties.last_modified.description
The last time a record was refreshed in our database. This may happen due to regular operational processes and does not necessarily indicate anything about the measurement has changed.
You can query this field using date-times or intervals, adhering to RFC 3339, or using ISO 8601 duration objects. Intervals may be bounded or half-bounded (double-dots at start or end).
Examples:

  - A date-time: "2018-02-12T23:20:50Z"
  - A bounded interval: "2018-02-12T00:00:00Z/2018-03-18T12:31:12Z"
  - Half-bounded intervals: "2018-02-12T00:00:00Z/.." or "../2018-03-18T12:31:12Z"
  - Duration objects: "P1M" for data from the past month or "PT36H" for the last 36 hours

Only features that have a `last_modified` that intersects the value of datetime are selected.