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/20015/?format=api
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "ob_id": 20015,
    "uuid": "96de05733b5d464885da0e1495626f7f",
    "title": "Sentinel 1B C-band Synthetic Aperture Radar (SAR): Interferometric Wide (IW) mode Single Look Complex (SLC) Level 1 data, Instrument Processing Facility (IPF) v2",
    "abstract": "This dataset contains Interferometric Wide swath (IW) Single Look Complex (SLC) C-band Synthetic Aperture Radar (SAR) data from the European Space Agency (ESA) Sentinel 1B satellite. Sentinel 1B was lanched on 25th April 2016 and provides continuous all-weather, day and night imaging radar data. The IW mode is the main operational mode. The IW mode supports single (HH or VV) and dual (HH+HV or VV+VH) polarisation. \r\n\r\nThe IW SLC product contains one image per sub-swath, per polarisation channel, for a total of three or six images. Each sub-swath image consists of a series of bursts, where each burst was processed as a separate SLC image. The individually focused complex burst images are included, in azimuth-time order, into a single sub-swath image, with black-fill demarcation in between\r\n\r\nUnlike SM and WV SLC products, which are sampled at the natural pixel spacing, the images for all bursts in all sub-swaths of an IW SLC product are re-sampled to a common pixel spacing grid in range and azimuth. The resampling to a common grid eliminates the need for further interpolation in case, in later processing stages, the bursts are merged to create a contiguous ground range, detected image.\r\n\r\n\r\nThese data are available via CEDA to any registered user.",
    "keywords": "Sentinel, radar, Synthetic Aperture Radar, SAR, Interferometric Wide, IW, Single Look Complex, SLC",
    "publicationState": "published",
    "dataPublishedTime": "2016-09-08T23:00:00",
    "doiPublishedTime": null,
    "updateFrequency": "asNeeded",
    "status": "ongoing",
    "result_field": {
        "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/20031/?format=api",
        "dataPath": "/neodc/sentinel1b/data/IW/L1_SLC/IPF_v2",
        "oldDataPath": [],
        "storageLocation": "internal",
        "storageStatus": "online",
        "volume": 1439933488233013,
        "numberOfFiles": 1692978,
        "fileFormat": "Image data files are in a binary format. Quicklook images are in png format. Manifest files with relevant metadata are in SAFE format."
    },
    "timePeriod": "https://api.catalogue.ceda.ac.uk/api/v2/times/9007/?format=api",
    "geographicExtent": "https://api.catalogue.ceda.ac.uk/api/v2/bboxes/1/?format=api",
    "nonGeographicFlag": false,
    "phenomena": [
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/22593/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/phenomona/22849/?format=api"
    ],
    "dataLineage": "Data collected and prepared by European Space Agency (ESA). Downloaded from the Collaborative Hub for use by the UK scientific community.",
    "removedDataTime": null,
    "removedDataReason": "",
    "language": "English",
    "identifier_set": [],
    "projects": [
        "https://api.catalogue.ceda.ac.uk/api/v2/projects/12321/?format=api"
    ],
    "observationcollection_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/20016/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/observationcollections/30129/?format=api"
    ],
    "responsiblepartyinfo_set": [
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/76077/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/76078/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/76080/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/146221/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/76075/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/76076/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/76079/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/105173/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/76081/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/76074/?format=api",
        "https://api.catalogue.ceda.ac.uk/api/v2/rpis/146278/?format=api"
    ],
    "procedureAcquisition": null,
    "procedureCompositeProcess": "https://api.catalogue.ceda.ac.uk/api/v2/composites/20019/?format=api",
    "procedureComputation": null,
    "permissions": [
        {
            "ob_id": "https://api.catalogue.ceda.ac.uk/api/v2/observations/2586/?format=api",
            "useLimitation": null,
            "accessConstraints": null,
            "accessCategory": "public",
            "accessRoles": null,
            "label": "public: None group",
            "licenceURL": "https://sentinel.esa.int/documents/247904/690755/Sentinel_Data_Legal_Notice",
            "licenceClassifications": "any"
        }
    ],
    "discoveryKeywords": [
        {
            "ob_id": 1138,
            "name": "NDGO0003"
        }
    ]
}