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/889/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 889,
    "uuid": "901e555641b5c68d9f41b15d7a2ab842",
    "title": "Cape Verde Atmospheric Observatory: NMHC measurements from dual channel Gas Chromatograph (2006 onwards)",
    "abstract": "Data from observations made at the Cape Verde Atmospheric Observatory (CVAO) which exists to advance understanding of climatically significant interactions between the atmosphere and ocean and to provide a regional focal point and long-term data. \r\n\r\nThe observatory is based on Calhau Island of São Vicente, Cape Verde at 16.848N, 24.871W, in the tropical Eastern North Atlantic Ocean, a region which is data poor but plays a key role in atmosphere-ocean interactions of climate-related and biogeochemical parameters including greenhouse gases. It is an open-ocean site that is representative of a region likely to be sensitive to future climate change, and is minimally influenced by local effects and intermittent continental pollution. \r\n\r\nThe dataset contains mixing ratio measurements of ethane, propane, iso-butane, acetylene and iso-pentane.",
    "keywords": "Cape Verde, NMHC",
    "publicationState": "published",
    "dataPublishedTime": "2010-09-17T13:42:19",
    "doiPublishedTime": null,
    "updateFrequency": "asNeeded",
    "status": "ongoing",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/890/?format=api",
        "dataPath": "/badc/capeverde/data/cv-dc-gc-fid",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 14505644,
        "numberOfFiles": 11,
        "fileFormat": "Data are NASA Ames formatted"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/3719/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/12/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/57005/?format=api"
    ],
    "dataLineage": "Data collected at Cape Verde Atmospheric Observatory before being transmitted back to UK where NCAS staff prepare data for archiving at BADC.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/identifiers/616/?format=api"
    ],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/875/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/5007/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/872/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/2900/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/2898/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/2901/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/2902/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/2903/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/2905/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/2899/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/2904/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/55561/?format=api"
    ],
    "procedureAcquisition": "https://api.catalogue.ceda.ac.uk/api/v2/acquisitions/892/?format=api",
    "procedureCompositeProcess": null,
    "procedureComputation": null,
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2522/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "registered",
            "accessRoles": null,
            "label": "registered: None group",
            "licenceURL": "http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
            "licenceClassifications": "any"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}