[DAS2] how to test features?

Andrew Dalke dalke at dalkescientific.com
Fri Jun 10 17:13:36 UTC 2005

> In DAS/1 the types response can optionally include a count of the 
> number
> of features available for that particular type and source.  I do think
> this would be a useful feature to preserve in DAS/2.

I don't think it would work that well.  Given the way we've
structured things it's possible the type/ hierarchy is shared
by several feature/ hierarchies.

My two mental models are:
  - a single server where different source/versions
      shares the same types/
  - a server which uses someone else's types/ and regions/
      as the reference, adding only features/

> From that
> information a client/validator could potentially tune its requested
> range to return on average a desired number of features.

My shot-in-the-dark guess is that the non-uniform distribution
of features lessens its usefulness.

> I don't think a server should return only some of the features that 
> meet
> the search criteria -- should return either all or none.  If a server
> decides that a client is requesting too much data, I think servers
> should be able to return some sort of "returned feature count too 
> large"
> error code response.

I can go along with that, though I would like to know what
a client is supposed to do if it gets that response and
if we should specify that a server should be able to return at
least (say) 10,000 features at a time.

>   And maybe in the source or versioned source
> response xml have an optional indication of how many features a server
> is willing to serve up in a single request, so clients can know this
> limit in advance.

In thinking some more about that - what would a client do
with that information?

					dalke at dalkescientific.com

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