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/19797/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 19797,
    "uuid": "676d7fef735b49d5926d3a38fc239d09",
    "title": "Digitised bulletins",
    "abstract": "Digitised bulletins",
    "keywords": "Ionosonde, Digitised bulletins",
    "publicationState": "working",
    "dataPublishedTime": null,
    "doiPublishedTime": null,
    "updateFrequency": "asNeeded",
    "status": "ongoing",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/19820/?format=api",
        "dataPath": "http://www.ukssdc.ac.uk/wdcc1/ionosondes/secure/iono_data.shtml",
        "oldDataPath": [],
        "storageLocation": "external",
        "storageStatus": "offline",
        "volume": 0,
        "numberOfFiles": 0,
        "fileFormat": "ASCII"
    },
    "timePeriod": null,
    "geographicExtent": null,
    "nonGeographicFlag": false,
    "phenomena": [],
    "dataLineage": "Data are collated by the UK Solar System Data Centre as part of its role as a World Data Centre (WDC)",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/19806/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/10944/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/74970/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/74966/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/74967/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/74972/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/74969/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/74968/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/74965/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/74971/?format=api"
    ],
    "procedureAcquisition": null,
    "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": []
}