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/32283/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 32283,
    "uuid": "c8b4b03778b145f79facce0af21237cb",
    "title": "Landsat 5 Thematic Mapper (TM) data",
    "abstract": "The Landsat Thematic Mapper (TM) sensor was carried onboard Landsats 4 and 5 from July 1982 to May 2012 with a 16-day repeat cycle, referenced to the Worldwide Reference System-2. Very few images were acquired from November 2011 to May 2012. The satellite began decommissioning activities in January 2013.\r\n\r\nThe Thematic Mapper (TM) is an advanced, multispectral scanning, Earth resources sensor designed to achieve higher image resolution, sharper spectral separation, improved geometric fidelity, and greater radiometric accuracy and resolution than the Multispectral Scanner (MSS) sensor. TM data are sensed in seven spectral bands simultaneously. A TM scene has an Instantaneous Field Of View (IFOV) of 30m x 30m in bands 1-5 and 7 while band 6 has an IFOV of 120m x 120m on the ground (band 6 was collected at 120 meters, but was resampled to 30 meters). Band 6 senses thermal (heat) infrared radiation. Landsat can only acquire night scenes in band 6. The approximate scene size is 170 km north-south by 183 km east-west (106 mi by 114 mi).",
    "keywords": "Landsat, USGS, NASA, TM",
    "publicationState": "published",
    "dataPublishedTime": "2021-07-07T12:59:07",
    "doiPublishedTime": null,
    "updateFrequency": "notPlanned",
    "status": "completed",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/32282/?format=api",
        "dataPath": "/neodc/landsat5/data/TM/",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 910781409269,
        "numberOfFiles": 25647,
        "fileFormat": "These data are provided by NASA/USGS in GeoTIFF format."
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/9020/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/529/?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/8334/?format=api"
    ],
    "observationcollection_set": [],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/143695/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/143696/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/143697/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/143698/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/143699/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/143700/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/145828/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/145829/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": "https://api.catalogue.ceda.ac.uk/api/v2/composites/32709/?format=api",
    "procedureComputation": null,
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2648/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "public",
            "accessRoles": null,
            "label": "public: None group",
            "licenceURL": "https://artefacts.ceda.ac.uk/licences/specific_licences/USGS_Copyright_Policy.pdf",
            "licenceClassifications": ""
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}