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/30193/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 30193,
    "uuid": "05cea0662aa54aa2b7e2c5811e09431f",
    "title": "Defra and JNCC Sentinel-1 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-1 data processed into a normalised radar backscatter product on a linear scale in dB. Products acquired from ESA are Ground-Range Detected (GRD) Interferometric Wide-swath (IW) in the dual VV+VH polarisation (DV) mode, where both VV and VH polarisations are collected.  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\nSentinel-1 scenes processed before July 2021 have had a strip of data clipped from their northern edge to remove an artefact caused by a deprecated processing method.  Details can be found in the lineage statement of the metadata for all affected scenes.",
    "keywords": "Analysis Ready Data,  Sentinel, Backscatter, Synthetic Aperture Radar, ARD",
    "publicationState": "published",
    "dataPublishedTime": "2020-03-30T10:59:05",
    "doiPublishedTime": null,
    "updateFrequency": "daily",
    "status": "ongoing",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/30194/?format=api",
        "dataPath": "/neodc/sentinel_ard/data/sentinel_1/",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 141620702520799,
        "numberOfFiles": 71998,
        "fileFormat": "These data are provided in Cloud Optimized GeoTIFF (COG) format. Each product comes with xml metadata file."
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/9028/?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/130442/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130438/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130437/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130440/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130445/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130441/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130444/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130443/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/130439/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": "https://api.catalogue.ceda.ac.uk/api/v2/composites/30196/?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"
        }
    ]
}