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/14299/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 14299,
    "uuid": "a7b87a912c494c03b4d2fa5ab8479d1c",
    "title": "ESA Greenland Ice Sheet Climate Change Initiative (Greenland_Ice_Sheet_cci): Greenland Surface Elevation Change 1992-2014, v1.2",
    "abstract": "This data set is part of the ESA Greenland Ice sheet CCI project. The data set provides surface elevation changes (SEC) for the Greenland Ice sheet derived from satellite (ERS‐1, ERS‐2, Envisat and Cryosat) radar altimetry.   The ice mask is based on the GEUS/GST land/ice/ocean mask provided as part of national mapping projects, and based on 1980’s aerial photography. The data from ERS and Envisat are based on a 5‐year running average, using combined algorithms of repeat‐track (RT), along‐track (AT) or cross‐over (XO) algorithms, and include propagated error estimates. \r\n\r\nIt is important to note that different processing algorithms were applied to the ERS‐1, ERS‐2, Envisat and CryoSat data;  for details see the Product User Guide (PUG), available on the CCI website and in the documentation section here. For ERS‐1, the radar data were processed using a cross‐over algorithm (XO) only. For ERS‐2 data and Envisat data in repeat mode, a combination of RT and XO algorithms was applied, followed by filtering. For across‐mission (i.e. ERS‐2‐Envisat) combinations, and for Envisat operating in a drifting orbit, an AT and XO combination was applied (the difference between RT and AT algorithms is that AT use reference tracks and searches for data in the vicinity of this track). For CryoSat data a binning/gridding and plane fit method has been applied, following by weak filtering (0.05 degree resolution).",
    "keywords": "Greenland Ice Sheet, ESA, CCI",
    "publicationState": "published",
    "dataPublishedTime": "2016-04-15T14:38:14",
    "doiPublishedTime": null,
    "updateFrequency": "",
    "status": "completed",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/14320/?format=api",
        "dataPath": "/neodc/esacci/ice_sheets_greenland/data/greenland_surface_elevation_change/v1.2",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 162098154,
        "numberOfFiles": 85,
        "fileFormat": "Files are provided in both NetCDF (.nc) and ASCII Gravsoft (.gri) format, as well as .png images.   \r\n\r\nIn ascii gravsoft format the data are stored row‐wise in E‐W rows, from N to S, headed by a two‐line label defining coordinate limits and projection. This format is the simplest possible ASCII grid format. Unknown values are flagged by 9999. The grid label for the CCI data is:\r\n‐3350000. ‐650000. ‐650000. 850000. 5000. 5000. (this is N1, N2, E1, E2, dN, DE in meter)\r\n‐70 ‐45 (minus reference latitude, central meridian in degrees)\r\nThe CCI data grid contains a total 541 x 301 points. First data value in file is thus the NW cormer (N = ‐650 km,E = ‐650 km) and last value the SE corner (N = ‐3350 km, E = 850 km). Stereographic projections have by default (0,0) at the North Pole.\r\n\r\nThe data use a Polar stereographic projection, WGS84 ellipsoid, with a reference latitude of 70N, and central meridian of 45W"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/3784/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/895/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/18459/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/55816/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/69204/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/69205/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/69207/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/69208/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/69209/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/83765/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/83766/?format=api"
    ],
    "dataLineage": "Data were processed by the ESA CCI Greenland Ice Sheet project team and supplied to CEDA in the context of the ESA CCI Open Data Portal Project.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/14317/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/14316/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/55396/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/55397/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/55398/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/55601/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/104918/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/105134/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/105312/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/55399/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/55602/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/55603/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/55604/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/55605/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": null,
    "procedureComputation": null,
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2553/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "public",
            "accessRoles": null,
            "label": "public: None group",
            "licenceURL": "https://artefacts.ceda.ac.uk/licences/specific_licences/esacci_icesheets_greenland_terms_and_conditions.pdf",
            "licenceClassifications": "any"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        },
        {
            "ob_id": 1140,
            "name": "ESACCI"
        }
    ]
}