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Re: [dxwg] Distribution definition [RDIDF]

From: Rob Atkinson via GitHub <sysbot+gh@w3.org>
Date: Mon, 24 Sep 2018 21:55:47 +0000
To: public-dxwg-wg@w3.org
Message-ID: <issue_comment.created-424138849-1537826146-sysbot+gh@w3.org>
Narrowing the scope, as proposed, breaks backwards compatibility with existing DCAT implementations.

Services that support queries against a dataset are never "informationally equivalent

If this restricted view is held, then any distrubution that supports accessing a file remotely, is by definiton not a dcat:Distribution but a dcat:SistributonService.  Just basic web architecture of allowing a HTTP HEAD request is sufficient to break information equivalence, and content negotiation over langauge or mime type also does. Different formats are not informationally equivalent - for example a CSV file loses relationships between attributes compared to complex properties:

CSV
id,value1, units1, value2,units2
1, 2.3, "m/s",6.7,"kg"

vs 
JSON
{ id: 1 ;
   value1: {  value: 2.3 ; units "m/s" ; }
  value2: { value: 6.7 ; units "kg" ; 
}

CSV holds less information because value1 and units1 need further out-of-band to be related to each other.

So - unless you can come with a robust statement about testability of information equivalence, it strikes me as a slippery slope with no huge value. 

OTOH Making an explicit statement that Distributions may not be informationally equivalent seems quite valuable, and makes services equivalent with distributions logically consistent



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Received on Monday, 24 September 2018 21:55:49 UTC

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