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/27793/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 27793,
    "uuid": "df502fe4715c4177ab5e4e367a99316b",
    "title": "Deriving Emissions related to Climate Change Network: CO2, CH4, N2O, SF6 and CO measurements from Heathfield Tall Tower, East Sussex",
    "abstract": "Measurements of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6) and carbon monoxide (CO) have been taken at Heathfield tall tower as part of the UK-DECC (Deriving Emissions related to Climate Change) Network. \r\n\r\nHeathfield (HFD) is a semi-rural UK site located 19 km south of Royal Tunbridge Wells (population ~118,000), in East Sussex, UK. This station is affiliated to the UK DECC (Deriving Emissions related to Climate Change) Network, and is operated by the National Physics Laboratory (NPL). CO2, CH4 and CO are  measured at a height of 50 m and 100 m above ground level. Due to the sites location, far from strong sources of local pollution, measurements from this site will be used to calculate emission maps of trace gas species in the UK in combination with other measurement stations in the UK and Ireland.\r\n\r\nDue to the sites location, far from strong sources of local pollution, measurements from this site are used to calculate emission maps of trace gas species in the UK in combination with other measurement stations in the UK (Bilsdale, Ridge Hill and Tacolneston) and Ireland (Mace Head).\r\n\r\nThis work was funded by  Business Energy and Industrial Strategy (BEIS) contracts TRN1028/06/2015 and TRN1537/06/2018  to the University of Bristol and through the National Measurement System at the National Physical Laboratory.",
    "keywords": "UK-DECC, Heathfield, trace gases",
    "publicationState": "published",
    "dataPublishedTime": "2019-09-26T13:06:13",
    "doiPublishedTime": null,
    "updateFrequency": "",
    "status": "ongoing",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/27794/?format=api",
        "dataPath": "/badc/uk-decc-network/data/previous_versions/Heathfield/",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 659805563,
        "numberOfFiles": 33,
        "fileFormat": "NetCDF"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/7438/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/2299/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/1633/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/23442/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/23448/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/23449/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/23451/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/25433/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/25434/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/25595/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/25596/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/25658/?format=api"
    ],
    "dataLineage": "Data were collected by the National Physics Laboratory/University of Bristol and deposited at the Centre for Environmental Data Analysis (CEDA) for archiving",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/27561/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/27499/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116188/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116204/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116184/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116183/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116186/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116185/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116187/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116189/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116205/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116180/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/116181/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/179871/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/179872/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/179873/?format=api"
    ],
    "procedureAcquisition": "https://api.catalogue.ceda.ac.uk/api/v2/acquisitions/27795/?format=api",
    "procedureCompositeProcess": null,
    "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"
        }
    ]
}