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/12701/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 12701,
    "uuid": "08ce7ca3941446ab9f66315d28a73631",
    "title": "ECMWF ERA-40: T159 spherical harmonic gridded model level forecast data (spfm)",
    "abstract": "This dataset contains T159 spherical harmonics gridded, model level, forecast timestep data from the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA) 40 program from January 1958 to December 2001. ERA-40 followed on from the ERA-15 re-analysis project.  Access limited to UK based academic researchers only. These data are GRIB formatted.",
    "keywords": "ECMWF, ERA, ERA-40, reanalysis, model, spherical harmonics grid, model level, forecast",
    "publicationState": "published",
    "dataPublishedTime": "2006-12-10T03:17:46",
    "doiPublishedTime": null,
    "updateFrequency": "notPlanned",
    "status": "completed",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/12715/?format=api",
        "dataPath": "/badc/ecmwf-e40/data/sp/fm/",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 24811699900,
        "numberOfFiles": 8025,
        "fileFormat": "Data are GRIB formatted"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/3450/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/1/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/60668/?format=api"
    ],
    "dataLineage": "Data were generated by the ERA-40 project at European Centre for Medium-Range Weather Forecasts (ECMWF) and stored within ECMWF's archives. The BADC then obtained a copy from the ECMWF archived and ingested into the BADC archives to aid wider academic use of these data.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/3809/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/3806/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/48527/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/48528/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/48526/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/48530/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/48531/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/48532/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/48533/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/48529/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": null,
    "procedureComputation": "https://api.catalogue.ceda.ac.uk/api/v2/computations/6659/?format=api",
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2536/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "registered",
            "accessRoles": null,
            "label": "registered: None group",
            "licenceURL": "https://artefacts.ceda.ac.uk/licences/specific_licences/ecmwf-era-products.pdf",
            "licenceClassifications": "any"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}