Map metadata used when Layer Metadata is available

[geographika]

As per the mailing list post at https://lists.osgeo.org/pipermail/mapserver-users/2020-October/081905.html: with regards to the GetMetadata requests:

Looking at the code it appears the "contact" metadata can only be retrieved at the MAP rather than LAYER level [2]. Is this something that should be available at LAYER level also, perhaps using "wms_attribution_title"?

Reply from @tomkralidis:

Good point. Perhaps if MAP.LAYER.METADATA.wms_attribution_title is available we can override accordingly

[tomkralidis]

@geographika thanks for filing this issue. When looking at the WMS Server documentation, I see the following metadata that can be applied from LAYER.METADATA with suggested elements they would override:

• wms_attribution_title: would override MAP.WEB.METADATA.*_contactorganization
• wms_attribution_onlineresource: would override MAP.WEB.METADATA.*_onlineresource

In addition to these overrides, would we want to turn OFF ALL the MAP.WEB.METADATA.*_contact_* metadata if either or both of the above are available? Or simply override the above two and keep the rest?

[geographika]

Tricky one. Initially I would have thought all MAP metadata would apply unless overridden at the LAYER level.

But could there be cases where a LAYER contact could have the wrong details from the MAP level? I guess this is something users would have to watch out for, and would need to override all relevant settings at the LAYER level.

Although is this possible? E.g. wms_contactelectronicmailaddress is only available at the MAP.WEB level (at least when listed in the docs). Maybe it can be set at the layer level even if not used by GetCapabilitites.

[tomkralidis]

Correct, contact metadata is only available at the MAP level (and not the LAYER level). So then are we proposing introducing the wms_contact* metadata at the LAYER level? Would this get much use outside of the Layer Metadata API? Also, this probably needs an RFC. Thoughts?

[jratike80]

But is there place for layer level contact information in the GetCapabilities schema http://schemas.opengis.net/wms/1.3.0/capabilities_1_3_0.xsd?

[tomkralidis]

@jratike80 right, there is not. So adding LAYER level contact metadata would only be valuable for the Layer Metadata API, unless there are other uses?

[geographika]

OK probably not worth adding then - it would likely confuse things. Main use case is to be able to show the source of a LAYER's data. The wms_attribution_title looks the most likely LAYER METADATA item to store this, so then it is a case of mapping it to an ISO XML property.

Looking at the sample GetMetadata at: https://demo.mapserver.org/cgi-bin/mapserv?map=/osgeo/mapserver/msautotest/world/world.map&request=GetMetadata&layer=world_latlong

I'm not sure which property (if any) fits this.

[tomkralidis]

We could map wms_attribution_title to gmd:otherCitationDetails (see example). Does this make sense for folks?