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/7964/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 7964,
    "uuid": "3d3cdd14cc2a6e299eb975538301365a",
    "title": "NCAVEO: Intergraph Z/I Imagery collected using a Digital Mapping Camera (DMC) during a flight by an Ordnance Survey aircraft at Chilbolton",
    "abstract": "As part of the 2006 Field Campaign of the Network for Calibration and Validation of EO data (NCAVEO), an Intergraph Z/I Imaging Digital Mapping Camera (DMC) was used to collect data in 4 spectral bands in the visible and near infrared, at a nominal ground resolution of 65cm. The Chilbolton site was flown over on the 9th June 2006 by the Ordnance Survey, resulting in 84 strips captured over the Area of Interest (2048 x 3072) with 60% overlap along the track. The data was orthorectified to the British National Grid using photogrammetric methods.\r\n\r\n",
    "keywords": "NCAVEO, INTERGRAPH IMAGERY, DMC, CHILBOLTON",
    "publicationState": "published",
    "dataPublishedTime": "2008-09-26T10:34:40",
    "doiPublishedTime": null,
    "updateFrequency": "notPlanned",
    "status": "completed",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/12685/?format=api",
        "dataPath": "/neodc/ncaveo_field/data/Ordnance_Survey_DMC",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 4634891575,
        "numberOfFiles": 171,
        "fileFormat": "Images are BSQ AND HDR files in ENVI format, with file names formatted as follows:\r\n‘instrument_location_YYYYMMDD_tracknumber_imagenumber_o(orthorectified)_version’"
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/2278/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/172/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [],
    "dataLineage": "These data were provided to NEODC by university of Southampton, who carried out work to convert formats to NASA-Ames, and write metadata documents. The metadata documents describing the processing are archived alongside the data as PDF files.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/identifiers/5177/?format=api"
    ],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/7827/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/7824/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/30128/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/32642/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/32647/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/32648/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/32641/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/32644/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/32645/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/32646/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/32643/?format=api"
    ],
    "procedureAcquisition": "https://api.catalogue.ceda.ac.uk/api/v2/acquisitions/7969/?format=api",
    "procedureCompositeProcess": null,
    "procedureComputation": null,
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2522/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "registered",
            "accessRoles": null,
            "label": "registered: None group",
            "licenceURL": "http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
            "licenceClassifications": "any"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}