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Re: Webby Data

From: Erik Wilde <dret@berkeley.edu>
Date: Tue, 13 Oct 2015 09:39:18 -1000
To: Phil Archer <phila@w3.org>, public-dwbp-comments@w3.org
Cc: "Tandy, Jeremy" <jeremy.tandy@metoffice.gov.uk>
Message-ID: <561D5DE6.8000603@berkeley.edu>
hello phil.

On 2015-10-10 00:40, Phil Archer wrote:
> On 09/10/2015 22:53, Erik Wilde wrote:
>> thanks a lot for getting the discussion about "web data" going (again).
>> we're probably getting closer, but i think we still have a bit of a
>> difference in perspective, because "webby data" is a necessary but not
>> sufficient condition to have hypermedia.
> True. But I don't think we're trying to define hypermedia any more than
> we're trying to define Linked Data. So for me, if we've met the
> necessary part, that's good. It's because we clearly weren't doing that
> that there has been a problem.

i hope i did not sound as if i wanted to define hypermedia. i was mostly 
struck by the fact that the web first and foremost is a 
hypermedia-driven information system, and that the document never 
mentioned the term or described that hypermedia is what should be 
driving any services that are provided to provide access to data.

>> the difference is that hypermedia is not (only) about linking data
>> (i.e., using "web data"), it's also about providing navigational
>> affordances to get things done with that data. this means that the links
>> are about *services* (or whatever you might call this).
> Yes, OK, I can add a line about that.

thanks. it might also be worthwhile to highlight the importance of 
resource granularity, because that's what deciding interaction granularity.

if you partition your data into more resources, you need more links, but 
you also may provide better ways for people to interact (GET or update 
or DELETE) with specific parts of your dataset.

it's up to the service designers to decide *how* they want this 
interaction granularity to look like, but that's one of the really 
important things to consider when designing web services.

granularity is a more natural thing to consider for some metamodels, and 
maybe not to much for others. but that's just a side-effect of how those 
metamodels work. in the end, what really should drive this is the 
intended *service granularity*.

http://dret.typepad.com/dretblog/2009/05/rest-and-rdf-granularity.html

> OK, so how about this (which I've included now in my proposed changes at
> [1].
> "These ideas are at the heart of the 5 Stars of Linked Data where one
> data point links to another, and of Hypermedia where links may be to
> further data or to services (or more generally 'affordances') that act
> on or relate to the data in some way. Examples include a bug reporting
> mechanisms, processors, a visualization engine, a sensor, an actuator
> etc. In both Linked Data and Hypermedia, the emphasis is put on the
> ability for machines to traverse from one resource to another following
> links that express relationships."

data and services are different things. you can do hypermedia in any 
metamodel (if you want to do it with RDF, hydra is a good starting 
point). and just by doing linked data, you're not doing hypermedia yet 
(which is my hydra is such a neat thing).

from my experience, it helps a lot to clearly and cleanly separate the 
issues of data and services. because then you can first talk about 
*what* to provide, and then *how* to provide it. and these are two 
different design decisions to make. often, the *what* is already decided 
(because the data model is a given), but then the delivery architecture 
(the *how*) still matters, and will have an impact in questions such as 
whether i can identify subresources in robust ways, so that i can for 
example submit issues/bugs about them.

>> On 2015-10-09 11:28, Phil Archer wrote:
>>> We had a BP that said "use persistent URIs as identifiers". And then  it
>>> said *Datasets* must be identified by persistent URIs. What it didn't
>>> say was that data points within the data should also be URIs where
>>> possible.
>> like i said above, i think talking about "web data" would be a great
>> first step (and thus i am very much in favor of it), but it's not the
>> full hypermedia story, which is *not just* about data.

i think this really is my main message: by putting "data on the web", 
you're deciding to deliver data through a hypermedia-driven service 
system. anybody making claims how to best do that has to address both 
the "data design" and the "service design" level.

>>> @Erik - is that doc going to stay on GitHub? Any chance it might find a
>>> more stable/permanent home? I really don't like linking to GH in a W3C
>>> Rec track document.
>> i'd be more than happy to (a) move this to some other place, and/or (b)
>> work on it to make it a bit easier to understand, or maybe add more
>> examples. i am open for suggestions what might be a better home for it.
>> for now i thought that maybe github is not such a bad place, at least as
>> long as this is mostly intended to be a starting point for a discussion
>> around "web data" in general.
> How about a Member Submission??

i am not affiliated with a member org right now, but i'd be more than 
happy to turn this into some kind of NOTE. which might also have the 
added benefit of getting more feedback before the final version.

thanks and cheers,

dret.

-- 
erik wilde | mailto:dret@berkeley.edu  -  tel:+1-510-2061079 |
            | UC Berkeley  -  School of Information (ISchool) |
            | http://dret.net/netdret http://twitter.com/dret |
Received on Tuesday, 13 October 2015 19:39:45 UTC

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