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/33384/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 33384,
    "uuid": "102909b1d169469f85c099a6f1686bad",
    "title": "JNCC Sentinel-2 indices Analysis Ready Data (ARD) Enhanced Vegetation Index (EVI)",
    "abstract": "EVI is a development on Normalised Difference Vegetation Index (NDVI).\r\n\r\nSentinel-Hub EVI description: \r\nIn areas of dense canopy cover, where leaf area index (LAI) is high, the blue wavelengths can be used to improve the accuracy of NDVI, as it corrects for soil background signals and atmospheric influences. The range of values for EVI is -1 to 1, with healthy vegetation generally around 0.20 to 0.80.\r\n\r\nEVI is calculated: EVI = 2.5 * ((NIR – RED) / ((NIR + (6 * RED) – (7.5 * BLUE)) + 1))\r\n\r\nSentinel 2 EVI = 2.5 * ((B8 – B4) / ((B8 + (6 * B4) – (7.5 * B2)) + 1))\r\n\r\nThese data have been created by the Joint Nature Conservation Committee (JNCC) as part of a Defra Natural Capital and Ecosystem Assessment (NCEA) project to produce a regional, and ultimately national, system for detecting a change in habitat conditions at a land parcel level. The first stage of the project is focused on Yorkshire, UK, and therefore the dataset includes granules and scenes covering Yorkshire and surrounding areas only. The dataset contains Enhanced Vegetation Index data derived from Defra and JNCC Sentinel-2 Analysis Ready Data.\r\n\r\nEVI files are generated for the following Sentinel-2 granules:\r\n•\tT30UWE\r\n•\tT30UXF\r\n•\tT30UWF\r\n•\tT30UXE\r\n•\tT31UCV \r\n•\tT30UYE\r\n•\tT31UCA\r\n\r\nAs the project continues, JNCC will expand the geographical coverage of this dataset and will provide continuous updates as ARD becomes available.",
    "keywords": "JNCC, ARD, EVI, Sentinel 2, EO indices, Analysis Ready Data, Sentinel",
    "publicationState": "removed",
    "dataPublishedTime": "2022-05-11T14:41:31",
    "doiPublishedTime": null,
    "updateFrequency": "",
    "status": "obsolete",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/33385/?format=api",
        "dataPath": "/neodc/sentinel_ard/indices/sentinel_2/evi/",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 970,
        "numberOfFiles": 1,
        "fileFormat": "These data are provided in Cloud Optimized GeoTIFF (COG) format."
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/9168/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/2907/?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": "2023-02-10T14:00:30",
    "removedDataReason": "These data have been removed due to errors in the processing. At present there are no plans to replace them.",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/30197/?format=api"
    ],
    "observationcollection_set": [],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/149061/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/149054/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/149055/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/149056/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/149057/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/149058/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/149059/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/149060/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": "https://api.catalogue.ceda.ac.uk/api/v2/composites/33406/?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"
        }
    ]
}