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/11195/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 11195,
    "uuid": "88f687c9ab627f980cfabbb0bc732e28",
    "title": "ADRIEX: Domain filling trajectories from UTRAJ model",
    "abstract": "The Aerosol Direct Radiative Impact Experiment (ADRIEX) was a joint UK Met Office/Natural Environment Research Council (NERC)/UK Royal Society/University of Oslo project aiming at improving our understanding of the radiative effects of anthropogenic aerosol and gases (ozone and methane) in the troposphere.\r\n\r\nThis dataset contains forecast trajectories computed using UTRAJ.\r\n\r\nThe term “particle trajectory” describes the path of a point which is blown by a time dependent wind field (i.e. (u, v, w) as a function of (x, y, z, t)). Trajectories following the analysed wind field are described by their coordinates (e.g. longitude, latitude, pressure) at regularly spaced time intervals. “Domain filling” refers to calculations where the arrival points of back trajectories (or release points for forward trajectories) form a dense, regular grid in a specified volume. The term “reverse” is used to indicate that the particles are followed backwards in time. Back trajectories are assumed to arrive on a 3D grid consisting of a stack of horizontal grids (regular in longitude and latitude) on a range of pressure levels. Forward trajectories are assumed to depart from similar grids. The trajectory length (time before arrival for back trajectories) is denoted by the letter T. Other fields can also be recorded following the trajectories: for example, temperature, specific humidity or potential vorticity. These extra fields are described as “attributes” and will be denoted by the variable C. The change in the value of an attribute over the length of a trajectory is denoted by C(0) − C(T).\r\n\r\n",
    "keywords": "ADRIEX, UTRAJ",
    "publicationState": "published",
    "dataPublishedTime": "2016-04-13T15:11:40",
    "doiPublishedTime": null,
    "updateFrequency": "notPlanned",
    "status": "completed",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/11196/?format=api",
        "dataPath": "/badc/adriex/data/forecasts/utraj-df/",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 2374278151,
        "numberOfFiles": 193,
        "fileFormat": "Data are netCDF or NASA Ames formatted"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/3116/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/51/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [],
    "dataLineage": "Trajectories and other forecast products calculated by John Methven (University of Reading), based on European Centre for Medium-Range Weather Forecasts (ECMWF) forecast wind fields, to support Aerosol Direct Radiative Impact Experiment (ADRIEX) flight planning.\r\n",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/identifiers/7463/?format=api"
    ],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/2968/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/2965/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/40130/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/40128/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/40131/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/40132/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/40133/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/72691/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/40129/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/72692/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/72693/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/72694/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": null,
    "procedureComputation": "https://api.catalogue.ceda.ac.uk/api/v2/computations/2981/?format=api",
    "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"
        }
    ]
}