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/12907/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 12907,
    "uuid": "a28c24d917e147dfab1abab37d3f6e06",
    "title": "ESA ALPHASAT: preprocessed radio propagation measurements at 20 GHz at Chilton, Oxfordshire  v1",
    "abstract": "Radio propagation measurements at 20 GHz at Chilton, Oxfordshire for the ESA funded Large Scale Assessment of KA/Q band atmospheric channel using the ALPHASAT TDP5 Propagation beacon signal.",
    "keywords": "ALPHASAT, radio propagation, ESA20 GHZ",
    "publicationState": "published",
    "dataPublishedTime": "2017-11-01T12:25:12",
    "doiPublishedTime": null,
    "updateFrequency": "notPlanned",
    "status": "completed",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/25338/?format=api",
        "dataPath": "/badc/asalasca/data/chilton/preprocessed/20ghz",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 24994168708,
        "numberOfFiles": 724,
        "fileFormat": "Data are NetCDF formatted."
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/6854/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/694/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/11943/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/11944/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/11945/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/11946/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/11947/?format=api"
    ],
    "dataLineage": "Data were collected by the project participants before processing and delivery to CEDA for archiving.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/12892/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/12893/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103875/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/49385/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/49386/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/49387/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/49384/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103872/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103873/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103874/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/103876/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/49388/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": null,
    "procedureComputation": "https://api.catalogue.ceda.ac.uk/api/v2/computations/12897/?format=api",
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2668/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "restricted",
            "accessRoles": "asalasca",
            "label": "restricted: asalasca group",
            "licenceURL": "https://artefacts.ceda.ac.uk/licences/rugl_versions/rugl_v1-0.pdf",
            "licenceClassifications": "any"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}