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/25285/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 25285,
    "uuid": "8f1ff8ea77534e08b03983685990a9b0",
    "title": "Penlee Point Atmospheric Observatory: Meteorological and chemical observations 2014- present",
    "abstract": "The Penlee Point Atmospheric Observatory (PPAO) was established by the Plymouth Marine Laboratory in May 2014 for long term observations of ocean-atmosphere interaction. The observatory is only a few tens of metres away from the water edge and 11m above mean sea level.\r\n\r\nThis dataset contains air temperature, dew point, wind speed and direction, rainfall, sulphur dioxide, ozone, carbon dioxide and methane measurements from Penlee Point Atmospheric Observatory from 2014-2017.\r\n\r\nAt the mouth of the Plymouth Sound, the site (50° 19.08' N, 4° 11.35' W) is exposed to marine air when the wind comes from 110° - 240°. Typical southwesterly winds tend to bring relatively clean background Atlantic air.  In contrast, winds from the southeast are often contaminated by exhaust plumes from passing ships. The PPAO is in close proximity to marine sampling stations that form the Western Channel Observatory, enabling better understanding of the ocean-atmosphere coupling.",
    "keywords": "Penlee, Atmospheric, Meteorology, Pollution, Chemistry, Ozone, Sulphur Dioxide, Carbon Dioxide, Rainfall, Wind, Methane",
    "publicationState": "published",
    "dataPublishedTime": "2017-10-18T09:40:51",
    "doiPublishedTime": null,
    "updateFrequency": "",
    "status": "ongoing",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/25286/?format=api",
        "dataPath": "/badc/penlee/data/met-o3-co2-ch4",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 329310993,
        "numberOfFiles": 22,
        "fileFormat": "Data are Ascii and NASA Ames formatted"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/6838/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/1870/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/25981/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/62124/?format=api"
    ],
    "dataLineage": "Data were collected by Plymouth Marine Laboratory and deposited at the Centre for Environmental Data Analysis (CEDA) for archiving.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/25288/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/24737/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/25287/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/24762/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/29924/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103593/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103589/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103590/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103591/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103592/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103594/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103595/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103596/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103588/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103613/?format=api"
    ],
    "procedureAcquisition": "https://api.catalogue.ceda.ac.uk/api/v2/acquisitions/25292/?format=api",
    "procedureCompositeProcess": null,
    "procedureComputation": null,
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2528/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "public",
            "accessRoles": null,
            "label": "public: None group",
            "licenceURL": "http://creativecommons.org/licenses/by/4.0/",
            "licenceClassifications": "any"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}