Get a list of Observation objects.

### Available end points:

- `/observations/` - Will list all Results in the database
- `/observations.json` - Will return all Results in json format. This can
also be achieved by using the accept header. `application/json`
- `/observations/<object_id>/` - Returns Results object with that id

### Available Methods:

- `GET`
- `HEAD`

### Available filters:

- `title`
- `uuid`
- `keywords`
- `status`
- `result_field`
- `discoveryKeywords`
- `updateFrequency`
- `nonGeographicFlag`
- `publicationState`
- `permissions`

### How to use filters:

These filters can be used like django query filters using __ for related model relationships.

- `/observations/?uuid=d594d53df2612bbd89c2e0e770b5c1a0`
- `/observations/?status=completed`
- `/observations/?results_field__dataPath__startswith=/neodc/esacci`
- `/observations/?discoveryKeywords__name=ESACCI`
- `/observations/?nonGeographicFlag=True`

Filters can be stacked to build an 'AND' relationship. E.g.

- `/observations/?publicationState__in=published,citable&nonGeographicFlag=True`
- `/observations/?publicationState__in=published,citable&discoveryKeyword__name=NDGO0003`

GET /api/v2/observations/4750/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 4750,
    "uuid": "0ccee9243541e8ce0f584ca601e770f3",
    "title": "Convective Storm Initiation Project (CSIP): UK Met Office High Resolution Radiosonde Data",
    "abstract": "The UK Met Office high resolution radiosonde data describe observations taken every 2 seconds by radiosondes from Met Office observation stations in the UK.  The dataset contains measurements of parameters such as temperature, wind speed and direction, and pressure.",
    "keywords": "CSIP, Radiosonde, Met Office, Met Éireann, meteorology",
    "publicationState": "published",
    "dataPublishedTime": "2006-08-17T10:20:03",
    "doiPublishedTime": null,
    "updateFrequency": "notPlanned",
    "status": "completed",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/4751/?format=api",
        "dataPath": "/badc/csip/data/ukmo-radiosondes",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 37181018,
        "numberOfFiles": 226,
        "fileFormat": "Data are ps formatted.\r\n\r\n"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/1349/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/721/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/10201/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/10206/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/10208/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/50539/?format=api"
    ],
    "dataLineage": "Data were collected by the Met Office before preparation and delivery to the Convective Storm Initiation Project (CSIP) participants and then to the BADC for archiving.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/identifiers/3191/?format=api"
    ],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/4614/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/4611/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/21734/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/21735/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/21736/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/21733/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/21737/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/21739/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/41124/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/41128/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/54589/?format=api"
    ],
    "procedureAcquisition": "https://api.catalogue.ceda.ac.uk/api/v2/acquisitions/4752/?format=api",
    "procedureCompositeProcess": null,
    "procedureComputation": null,
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2532/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "restricted",
            "accessRoles": "ukmo_wx",
            "label": "restricted: ukmo_wx group",
            "licenceURL": "https://artefacts.ceda.ac.uk/licences/specific_licences/ukmo_agreement.pdf",
            "licenceClassifications": "academic"
        },
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2533/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "restricted",
            "accessRoles": "ukmo_wx_gov",
            "label": "restricted: ukmo_wx_gov group",
            "licenceURL": "https://artefacts.ceda.ac.uk/licences/specific_licences/ukmo_agreement_gov.pdf",
            "licenceClassifications": "policy"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}