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/26855/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 26855,
    "uuid": "1d8f70a7badd423babf3febc4dabec4c",
    "title": "Sea-viewing Wide Field-of-view Sensor (SeaWiFS) - Level 0 data from NEODAAS Dundee Satellite Receiving Station",
    "abstract": "This dataset provides optical level 0 ocean colour data. The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September 1997 until the end of mission in December 2010. SeaWiFS had 8 spectral bands from 412 to 865 nm. It collected global data at 4 km resolution, and local data (limited on board storage and direct broadcast) at 1 km. The mission and sensor were optimised for ocean colour measurements, with a local noon (descending) equator crossing time orbit, fore-and-aft tilt capability, full dynamic range, and low polarisation sensitivity. The data were transferred to CEDA when the Dundee Satellite Receiving Station NERC Earth Observation Data Acquisition and Analysis Service (NEODAAS Dundee node) facility was closed to continue the long term archive.",
    "keywords": "Ocean Colour, SeaStar, SeaWiFS, NEODAAS",
    "publicationState": "published",
    "dataPublishedTime": "2020-05-06T12:54:21",
    "doiPublishedTime": null,
    "updateFrequency": "",
    "status": "completed",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/26857/?format=api",
        "dataPath": "/neodc/seawifs/data",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 1009162845002,
        "numberOfFiles": 28012,
        "fileFormat": "These data are in DAT file format."
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/7232/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/529/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [],
    "dataLineage": "Data taken from the NEODAAS Dundee Satellite Receiving Station to continue the long term archive.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/30202/?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/129289/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/129290/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/129288/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/114896/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/129432/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/142500/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/142501/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/129435/?format=api"
    ],
    "procedureAcquisition": "https://api.catalogue.ceda.ac.uk/api/v2/acquisitions/29928/?format=api",
    "procedureCompositeProcess": null,
    "procedureComputation": null,
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2657/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "public",
            "accessRoles": null,
            "label": "public: None group",
            "licenceURL": "https://www.earthdata.nasa.gov/engage/open-data-services-software-policies/data-use-guidance",
            "licenceClassifications": "any"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}