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/27559/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 27559,
    "uuid": "4370dacd17544eb781aa1e51cc4dc633",
    "title": "Deriving Emissions related to Climate Change Network: CO2, CH4, N2O, and SF6 measurements from Ridge Hill Tall Tower, Herefordshire",
    "abstract": "High frequency measurements of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and sulfur hexafluoride (SF6) have been taken at Ridge Hill tall tower as part of the UK DECC (Deriving Emissions linked to Climate Change) Network. \r\n\r\nRidge Hill (RGL) is a rural UK site located 13 km south-east of Hereford (population ~55,000), and 30 km south-west of Worcester (population ~94,000), in Herefordshire, UK.  Measurements of SF6 and N2O have been taken using gas chromatography with an electron capture detector (GC-ECD), sampling from a height of 90 m above ground level. Measurements are also taken from inlet heights of 45 m and 90 m above ground level using laser-based techniques for CO2 and CH4. Due to the location of the site, 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, Tacolneston and Heathfield) 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.",
    "keywords": "UK-DECC, Ridge Hill, trace gases",
    "publicationState": "published",
    "dataPublishedTime": "2019-09-04T10:07:04",
    "doiPublishedTime": null,
    "updateFrequency": "",
    "status": "ongoing",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/27562/?format=api",
        "dataPath": "/badc/uk-decc-network/data/previous_versions/Ridge_Hill/",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 526200486,
        "numberOfFiles": 19,
        "fileFormat": "NetCDF"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/7392/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/2402/?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/23445/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/23446/?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/25429/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/25430/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/25431/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/25432/?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/25435/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/25436/?format=api"
    ],
    "dataLineage": "Data were collected by the 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/115263/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115260/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115259/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115257/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115266/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115261/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115258/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115262/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115268/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/115265/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/179843/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/179874/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/179875/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/179876/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/179877/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/179878/?format=api"
    ],
    "procedureAcquisition": "https://api.catalogue.ceda.ac.uk/api/v2/acquisitions/27557/?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"
        }
    ]
}