add thumbnail/graphicoverview to the core record model

[pvgenuchten]

A suggestion to add thumbnail (graphicoverview in iso19139) to the core model as optional field.
Thumbnail is quite common in for example https://schema.org/thumbnailUrl and opengraph

[pvgenuchten]

What kind of feedback is needed?

Having a thumbnail for records is a common use case. The thumbnail is displayed in search results:

But it can also be used to add an opengraph:image to the html representation, so the thumbnail is shown when you include a link to the record in social media

[pvretano]

@pvgenuchten we are waiting to hear back from more implementors. That will take time.
As far as I can recall, thumbnail was never a CSW core queryable either. Don't get me wrong, I use thumbnails too (see: https://www.pvretano.com/cubewerx/cubeserv/default/ogcapi/catalogues/collections/sentinel1cat/items) but its not like you can use thumbnail in a query expression. Of course, you are not prevented from including it as a record property in your community of interest.

[pvgenuchten]

Thank you Peter, indeed I considered such a feedback scenario, no problem.

I agree that thumbnail is not supposed to be a queryable (maybe as true/false, e.g. hasThumbnail)
But I would be interested if everybody uses a similar key for it, and not a mix of thumbnail, thumbnailUri, image, graphicOverview, etc...

[MichaelGordon]

From Ordnance Survey's point of view, we will usually use a thumbnail for our products and datasets, so this would definitely be useful to include as an optional attribute in records.

[m-mohr]

In STAC, this is part of the assets. As there are no assets here, the next logical place for thumbnails would simply be a link with a pre-defined rel type. For example:

{
  href: 'https://example.com/logo.png',
  rel: 'thumbnail',
  type: 'image/png'
}

[pvretano]

19-APR-2021: Add a recommendation to the specification for this particular use case since it has come up a few times. The only difference is that we would use the link relation 'preview' rather than thumbnail since the former is an official IANA link relation. See: https://tools.ietf.org/html/rfc6903#section-3

[m-mohr]

Yes, that sounds good to me. Indeed, thumbnail (and overview) are just the roles in STAC. I think STAC should also mention preview as rel type though, it's the more general way of adding thumbnails in comparison to assets.

[m-mohr]

PR for STAC: radiantearth/stac-spec#1092

[tomkralidis]

I think thumbail / graphicoverview is pertinent and valuable from a MetOcean perspective as well (as a returnable). +1 to express as a link with rel: preview.

[tomkralidis]

Discussed as the July 2021 OGC API Virtual Code Sprint, will move this to the Part 2 (dataset record) once proposed.

[pvretano]

09-AUG-2021: This issue can be closed as it will become part of #130. Basically, in #130 there will be a link related of preview to point to a thumbnail. So, the thumbnail will not be part of the core.