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/5894/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 5894,
    "uuid": "3f9d45db58e81d71535a2484439d50b2",
    "title": "UTLS-Ozone ITOP: TOMCAT atmospheric CO, NOX and O3 trajectory model output",
    "abstract": "Study of intercontinental transport of air pollutants by means of coordinated flights over the East coast of North America, the Azores and the West coast of Europe. ITOP was a component of the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT), an international initiative which coordinated the efforts of various American and European groups who developed plans for field campaigns in the summer of 2004, with the aim of improving our understanding of the factors determining air quality over the two continents and over remote regions of the North Atlantic. \r\n\r\nThis dataset contains TOMCAT atmospheric CO, NOX and O3 trajectory model output. Plot images are available for NOX, CO and O3.",
    "keywords": "UTLS, ITOP, Model, Chemistry",
    "publicationState": "published",
    "dataPublishedTime": "2007-03-14T02:23:33",
    "doiPublishedTime": null,
    "updateFrequency": "notPlanned",
    "status": "completed",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/5895/?format=api",
        "dataPath": "/badc/itop/data/forecasts_and_analyses/tomcat",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 552726375,
        "numberOfFiles": 1345,
        "fileFormat": "Data are ASCII formatted. Plots are PNG formatted"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/1723/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/129/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [],
    "dataLineage": "Near-real-time chemical analyses produced by the University of Cambridge using the TOMCAT chemical transport model. Data provided to the BADC as is in 2004.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/identifiers/3831/?format=api"
    ],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/12053/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/5813/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/25121/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/25119/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/25122/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/25123/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/25124/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/25126/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/25120/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/25125/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/56039/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": null,
    "procedureComputation": "https://api.catalogue.ceda.ac.uk/api/v2/computations/5896/?format=api",
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2578/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "restricted",
            "accessRoles": "ecmwftrj",
            "label": "restricted: ecmwftrj group",
            "licenceURL": "https://artefacts.ceda.ac.uk/licences/specific_licences/ukmo_agreement.pdf",
            "licenceClassifications": "academic"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}