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/3493/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 3493,
    "uuid": "e7f22f3c7ca0d900d5bc867a14843cfa",
    "title": "Chilbolton Facility for Atmospheric and Radio Research (CFARR) Drop Counting Raingauge Data, Sparsholt College Site",
    "abstract": "Data were collected by Chilbolton Facility for Atmospheric and Radio Research (CFARR) Raingauges from 15th of March 2002 to the present at Sparsholt College, Hampshire.\r\n\r\nThe dataset contains measurements of rainfall accumulation as measured by RAL Rapid Response Drop Counting rain gauges.",
    "keywords": "CFARR, rainfall, rain gauge",
    "publicationState": "published",
    "dataPublishedTime": "2003-09-20T14:36:32",
    "doiPublishedTime": null,
    "updateFrequency": "continual",
    "status": "ongoing",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/3494/?format=api",
        "dataPath": "/badc/chilbolton/data/raingauge_sparsholt",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 347087172,
        "numberOfFiles": 6449,
        "fileFormat": "Data are netCDF formatted."
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/973/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/59/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/22455/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/50512/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/54762/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/54763/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/54764/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/55311/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/55313/?format=api"
    ],
    "dataLineage": "Data are collected by 4 radar systems, of which the largest is the 3 GHz Doppler radar (CAMRa), and 4 lidar systems, at Chilbolton Observatory, Hampshire.\r\nData are prepared by Chilbolton Facility for Atmospheric and Radio Research (CFARR) staff prior to submission to BADC for archiving.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/identifiers/2362/?format=api"
    ],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/3464/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/3461/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/7378/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/14886/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/14887/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/14888/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/14889/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/14891/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/44233/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/44237/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/14885/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/44234/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/44235/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/44236/?format=api"
    ],
    "procedureAcquisition": "https://api.catalogue.ceda.ac.uk/api/v2/acquisitions/3495/?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"
        }
    ]
}