Noise Level Observed

Description

It represents an observation of those acoustic parameters that estimate noise pressure levels at a certain place and time. This entity is primarily associated with the Smart City and environment vertical segments and related IoT applications.

Data Model

The data model is defined as shown below:

  • id : Unique identifier.

  • type : Entity type. It must be equal to NoiseLevelObserved.

  • dateCreated : Entity's creation timestamp.

    • Attribute type: DateTime
    • Read-Only. Automatically generated.
  • dateModified : Last update timestamp of this entity.

    • Attribute type: DateTime
    • Read-Only. Automatically generated.
  • location : Location of this observation represented by a GeoJSON geometry.

  • address : Civic address of this observation.

  • name : Name given to this observation.

    • Normative References: [https://schema.org/name]
    • Optional
  • description : Description given to this observation.

    • Normative References: [https://schema.org/description]
    • Optional
  • dateObserved : The date and time of this observation represented by an ISO8601 interval. As a workaround for the lack of support of Orion Context Broker for datetime intervals, it can be used two separate attributes: dateObservedFrom, dateObservedTo.

    • Attribute type: ISO8601 interval represented as Text.
    • Optional
  • dateObservedFrom : Observation period start date and time. See dateObserved.

  • dateObservedTo : Observation period end date and time. See dateObserved.

  • refDevice : A reference to the device which captured this observation.

    • Attribute type: Reference to an entity of type Device
    • Optional
  • sonometerClass : Class of sonometer (0, 1, 2) according to ANSI used for taking this observation. This attribute is useful when no device entity is associated to observations. It allows to convey, roughly, information about the precision of the measurements.

    • Attribute type: Text
    • Allowed values: one of ("0", "1", "2")
    • Optional
  • refPointOfInterest : A reference to a point of interest associated to this observation.

    • Attribute type: Reference to an entity of type PointOfInterest
    • Optional

Representing acoustic parameters

The number of acoustic parameters measured can vary. For each acoustic measurand there MUST be an attribute which name MUST be exactly equal to the acoustic measurand name, as follows: + Attribute name: Equal to the name of the measurand, for instance LAeq, LAmax. It must correspond to a term defined at http://www.acoustic-glossary.co.uk/definitions-l.htm, with the only exception that those measurands which name contains a , char, such char shall be substituded by the _ char. For instance, the measurand "LAeq,d" shall be represented by an Attribute which name shall be LAeq_d. + Attribute type: Number + Attribute value: corresponds to the value for the measurand as a number expressed in decibels. + Attribute Metadata: + `description_: short description of the measurand. (optional) + Normative References: https://schema.org/description

Representing weather conditions

There are two options for representing them:

  • A/ Through a linked entity of type WeatherObserved (attribute named refWeatherObserved) which will capture the associated weather conditions.
  • B/ Adding weather-related properties defined at WeatherObserved.

Note: JSON Schemas only capture the NGSI simplified representation, this means that to test the JSON schema examples with a FIWARE NGSI version 2 API implementation, you need to use the keyValues mode (options=keyValues).

Examples of use 1 (Normalized Format)

    {
      "id": "Vitoria-NoiseLevelObserved-2016-12-28T11:00:00_2016-12-28T12:00:00",
      "type": "NoiseLevelObserved",
      "location": {
        "type": "geo:json",
        "value": {
          "type": "Point",
          "coordinates": [-2.6980, 42.8491]
        }
      },
      "dateObservedFrom": {
        "type": "DateTime",
        "value": "2016-12-28T11:00:00"
      },
      "dateObservedTo": {
        "type": "DateTime",
        "value": "2016-12-28T12:00:00"
      },
      "LAeq":{
        "value": 67.8,
        "metadata": {
          "description": {
            "value": "A-weighted, equivalent, sound level"
          }
        }
      },
      "LAmax": {
        "value": 94.5,
        "metadata": {
          "description": {
            "value": "A-weighted, maximum, sound level"
          }
        }
      },
      "LAS": {
        "value": 91.6,
        "metadata": {
          "description": {
            "value": "A-weighted, Slow, sound level"
          }
        }
      },
      "LAeq_d": {
        "value": 65.4,
        "metadata": {
          "description": {
            "value": "A-weighted, equivalent, day period, sound level"
          }
        }
      }
    }

Examples of use 2 (?options=keyValues simplified representation for data consumers)

{
        "id": "Vitoria-NoiseLevelObserved-2016-12-28T11:00:00_2016-12-28T12:00:00",
        "type": "NoiseLevelObserved",
        "LAS": 91.6,
        "LAeq": 67.8,
        "LAeq_d": 65.4,
        "LAmax": 94.5,
        "dateObservedFrom": "2016-12-28T11:00:00.00Z",
        "dateObservedTo": "2016-12-28T12:00:00.00Z",
        "location": {
            "type": "Point",
            "coordinates": [
                -2.698,
                42.8491
            ]
        }
}

Open Issues

References