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/27583/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 27583,
    "uuid": "67074956dd8b45a59f3fca8c60eca9b7",
    "title": "Sentinel 1 Analysis-Ready Data for the Committee on Earth Observation Satellites (ARD4CEOS) over Plymouth",
    "abstract": "This reference only dataset contains Sentinel-1 data that has been modified to provide a Normalised Radar Backscatter, Analysis Ready Dataset over Plymouth.  Two months' of data are provided for each area in the CARD4L v3.2.2 standard format.  The data is designed to be used with the ESA SNAP toolbox. UK Analysis-Ready Data (ARD) tests in support of the Committee on Earth Observation Satellites (CEOS) Standards is a project run by the Group on Earth Observations (GEO)/CEOS office.  The purpose of the project was to demonstrate the UK's ability to produce ARD to the specified CEOS Analysis Ready Data for Land (CARD4L) standards. The GEO/CEOS office is hosted by NCEO and funded by UK Space Agency, DEFRA and NERC.",
    "keywords": "ARD, Sentinel",
    "publicationState": "published",
    "dataPublishedTime": "2019-10-03T15:51:14",
    "doiPublishedTime": null,
    "updateFrequency": "",
    "status": "completed",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/27584/?format=api",
        "dataPath": "/neodc/ard4ceos/data/plymouth/",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 89994207065,
        "numberOfFiles": 200,
        "fileFormat": "These data are provided in HDR and IMG format suitable for use with the ESA SNAP toolbox. Each product comes with various masks and metadata files."
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/7389/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/2405/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [],
    "dataLineage": "Contains modified Copernicus Sentinel data 2018; Example ARD dataset produced under the 'UK Analysis-Ready Data Tests in Support of CEOS Standards' project. Data delivered to CEDA for archiving.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/27545/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/30129/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115337/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115341/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/143450/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/143451/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115343/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115340/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115338/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115339/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115342/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": "https://api.catalogue.ceda.ac.uk/api/v2/composites/27544/?format=api",
    "procedureComputation": null,
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2526/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "public",
            "accessRoles": null,
            "label": "public: None group",
            "licenceURL": "http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
            "licenceClassifications": "any"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}