Streamflow
- Thushara Gunda (Unlicensed)
Table 1: The STA data model definitions and example mappings to NM/federal agency datasets regarding streamflow measurements
| SensorThings Entity | Description | |
|---|---|---|---|
Metadata | Location | A unique coordinate or area on the surface of the earth | Location in latitude and longitude (USGS - publicly also represented as deg-min-sec) OSE data is in UTM Zone 13, NAD83 (OSE location data is within GIS dataset, need to link to IDs below - not publicly displayed due to security concerns - vandalism) |
Thing | Some real-world entity with which one or more Sensors are associated | USGS 08324000 OSE website has string IDs: “Citizens/BID” - associated numerical unique identifiers are available on the back end | |
Datastream | A collection of Observations about an ObservedProperty produced by a Sensor associated with a Thing | Time series, Hydrograph | |
Datastream/observationType | The type of observation, codified in the Observations and Measurements data standard. Types include Categorical (defined text), Count (integer), Measurement (continuous number), Observation (free text), and TruthObservation (True/False) | Measurement | |
Datastream/unitOfMeasurement | A three-item definition of the unit of measurement, including its name, symbol, and link to the definition (preferably to one provided in an established ontology such as UCUM Specification or http://qudt.org/) | cfs (cubic feet/sec) - discharge feet - gage height | |
Sensor | The procedure used to provide a Datastream. Can be a particular data recording device model, or a defined procedure followed by a human observer. If applicable, a specific instance (e.g. a sensor model and serial number) | continuous: pressure transducer; shaft encoders; radar; bubbler; (radios/satellites for communication of data from field to HQ at OSE) manual/field measurements - might be taken at a continuous site but logged differently than real-time collections (esp. for OSE) | |
ObservedProperty | The raw or processed phenomenon (quantitative or qualitative) being measured for the Datastream. Preferably including a link to a definition provided by an established ontology or controlled vocabulary such as the ODM2 Controlled Vocabularies or http://qudt.org/) | Discharge Gage Height (“staff plates” might be field checks)
| |
OPTIONAL: FeatureOfInterest | The real-world feature that the Observations are about. This may or many not be different from the Location where the Thing on which the Sensor is mounted. Can include a JSON-formatted point location or a polygon or collections thereof. | Purpose/decisions that are informed by streamflow measurements (e.g., apportionment to water users) but this is typically not documented River/Acequia name associated with measurement location | |
Data | Observation | A single measurement value including the result, time values, and other metadata. Information on the ObservedProperty that was measured by what Sensor is provided by the Datastream these observations are in. Features of Interest are linked for each observation as well. Observations are linked to (collected in) Datastreams | Flow Measurement |
Observation/result | The actual measured value, with valid values defined in observationType and units defined in unitsOfMeasurement, both provided by Datastream | Discharge (e.g., 17.9) Gage Height (e.g., 2.38) (value read is sometimes transformed prior to display, e.g., pressures to height) | |
Observation/phenomenonTime | The date+time (or interval) in ISO 8601 format (YYYY-MM-DDT:HH:MM:SS-Z) when the observation occured | 2020-02-09 18:15 (15-minute intervals) (discrete measurement at the end of the 15-minute interval) | |
OPTIONAL: Observation/resultTime | The date+time that the result was generated. May be the same as phenomenonTime |
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OPTIONAL: Observation/validTime | The date+time interval during which the Observation can be used (often used for provisional values that are replaced by QA/QC’d observations) |
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OPTIONAL: Observation/resultQuality | A description of the result Quality. Will vary according to agency practice. Can use ODM2 controlled vocabulary for data quality types as a guide. | Precision (e.g., 1/10 for discharge and 1/100 for gage height) Tagged Provisional vs. Approved for data. Pre-data quality check for USGS = Provisional (usually turned around within a target of 150 days). OSE real-time data does not contain data quality flags. per John Mumm, this is really a “raw, real-time data that's an estimate” Note: prior to 2007, used daily values. Nowadays, it’s at 15-minute intervals |