[GeoSciML] Changes needed to get qualified lithology query working

Sen, Marcus A. mase at bgs.ac.uk
Fri Jun 14 09:14:59 EDT 2013


I'd like to check my recollection of our conclusions about what is needed to get a useful lithology query working following the St Petersburg meeting.

In summary, for OneGeology we would like to be able to query a WFS server to return something like "all the GeologicUnits which have at least 25% sandstone lithology. This does not seem to be possible currently.

The first factor that seemed to prevent it was as a result of the restricted subset of XPath which FES says implementations are obliged to support. This problem turned out to be soluble in our example although the general problem of more complex queries remains.

The second problem was the fact that we can't extract one of the numbers from a swe:Quantity range to do a numerical comparison on using FES. If the range was encoded with separate tags for upper and lower bounds we could do. At the moment, as we are re-using SWE this possibility is not available. Eric emailed Alexandre Robin to ask whether the SWE working group would consider modifying SWE to allow an encoding of a range with separate tags. Even if they would, I guess that this wouldn't become a published standard for some time.

I have a vague recollection that we may have mentioned the idea of making a small modification to GeoSciML 3.x so that we could encode a range in separate tags pre-emptively before SWE does if we thought it was going to happen at some stage. This would allow us to pass John Laxton's "laugh test" of being able to do the above query.

(In the longer term we have more general thinking to do about how queryable we expect such services to be, whether we need a separate query profile from the data model to support the queries we want to be able to do etc.)

Could Eric, in particular, confirm whether my summary is correct and could Olly comment on whether modifying GeoSciML 3.x is an idea with any traction or not?

Any other comments, feel free...

Marcus



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