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/30199/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 30199,
    "uuid": "bf9568b558204b81803eeebcc7f529ef",
    "title": "Defra and JNCC Sentinel-2 Analysis Ready Data (ARD)",
    "abstract": "These data have been created by the Department for Environment, Food and Rural Affairs (Defra) and Joint Nature Conservation Committee (JNCC) in order to cost-effectively provide high quality, Analysis Ready Data (ARD) for a wide range of applications. The dataset contains modified Copernicus Sentinel-2 (Level 1C data processed into a surface reflectance product (Level 2)). Defra and JNCC data were processed on separate platforms using a common specification to produce complementary outputs up to and including the acquisition date 23/06/2023. Data acquired after that date were processed on a single platform to the same specification.\r\n\r\nThe majority of data captured between July 2015 and August 2017 was processed by Aberystwyth University for Defra and later updated by JNCC to the same specification as the rest of this dataset.  Please see the image-level metadata for details of data lineage and processing.\r\n\r\nThe Sentinel-2 ARD filename format was changed in April 2023.  Filenames of data acquired on or after 01/04/2023 include the timestamp of data generation and display image latitude and longitude to a consistent number of significant figures preceded by ‘n’ (North) and ‘e/w’ (East / West).  Filenames of data acquired before this date do not include the data generation timestamp and display latitude and longitude to varying significant figures not preceded by ‘n’ and ‘e/w’.",
    "keywords": "Analysis Ready Data,  Sentinel, Surface Reflectance, ARD",
    "publicationState": "published",
    "dataPublishedTime": "2020-03-30T11:16:01",
    "doiPublishedTime": null,
    "updateFrequency": "",
    "status": "ongoing",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/30198/?format=api",
        "dataPath": "/neodc/sentinel_ard/data/sentinel_2/",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 90218995011176,
        "numberOfFiles": 527687,
        "fileFormat": "These data are provided in Cloud Optimized GeoTIFF (COG) format. Each product comes with valid pixel, topographic shadow, saturated pixel and cloud masks and metadata files"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/9029/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/2609/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [],
    "dataLineage": "Data were produced by the project team and supplied for archiving at the Centre for Environmental Data Analysis (CEDA).",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/30197/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/44948/?format=api"
    ],
    "observationcollection_set": [],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130457/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130453/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130452/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130455/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130456/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130458/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130459/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130460/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130454/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": "https://api.catalogue.ceda.ac.uk/api/v2/composites/30201/?format=api",
    "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"
        }
    ]
}