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Re: Area of spatial objects

From: Krzysztof Janowicz <janowicz@ucsb.edu>
Date: Fri, 26 Oct 2018 08:17:37 -0700
To: Simon.Cox@csiro.au, frans.knibbe@geodan.nl
Cc: public-sdwig@w3.org
Message-ID: <cdbb0740-56d0-d7dc-a356-661dff132738@ucsb.edu>
On 10/26/18 12:19 AM, Simon.Cox@csiro.au wrote:
>
> Yes, it is the SI unit, but units are not inherent in the definition 
> of the quantity-kind `area`.
>
> Binding units of measure into the quantity-type definition is a 
> convenient shortcut in some application contexts, but this conflates 
> two concepts so the result is no longer a quantity-kind, but is a 
> “scaled-quantity-kind”.
>
> There are other units of measure used for area.
>

Very well said and an important distinction. The square meter is the 
basis for the scalar, not the property itself.


> Simon
>
> *From:*Frans Knibbe [mailto:frans.knibbe@geodan.nl]
> *Sent:* Thursday, 25 October, 2018 21:11
> *To:* Cox, Simon (L&W, Clayton) <Simon.Cox@csiro.au>
> *Cc:* public-sdwig@w3.org
> *Subject:* Re: Area of spatial objects
>
> Op do 25 okt. 2018 om 03:42 schreef <Simon.Cox@csiro.au 
> <mailto:Simon.Cox@csiro.au>>:
>
>     Unfortunately http://dbpedia.org/ontology/area is /not/ general -
>     it is bound to m^2 .
>
> It is bound to the square meter, yes. But isn't the square meter the 
> general (SI) unit of area?
>
> Besides that, having the unit in the definition of the quantity could 
> be seen as an advantage - no need to repeat the unit for each measurement.
>
> Regards,
>
> Frans
>
>     http://qudt.org/vocab/quantity#Area is good-ish, but QUDT v2 has
>     been in the pipeline for several years now (more than 5) but its
>     publication is stalled L
>
>     *From:*Frans Knibbe [mailto:frans.knibbe@geodan.nl
>     <mailto:frans.knibbe@geodan.nl>]
>     *Sent:* Wednesday, 24 October, 2018 18:46
>     *To:* public-sdwig@w3.org <mailto:public-sdwig@w3.org>
>     *Subject:* Re: Area of spatial objects
>
>     Hi Nick,
>
>     A good general property for specifying area could be
>     http://dbpedia.org/ontology/area. But since you are already using
>     QUDT, how about http://qudt.org/vocab/quantity#Area?
>
>     As for relating a feature to different areas depending on CRS, I
>     think it would be best to first link a feature to geometries (a
>     different geometry for each CRS) and then link each geometry to
>     both a CRS and an area.
>
>     Greetings,
>
>     Frans
>

-- 
Krzysztof Janowicz

Geography Department, University of California, Santa Barbara
4830 Ellison Hall, Santa Barbara, CA 93106-4060

Email: jano@geog.ucsb.edu
Webpage: http://geog.ucsb.edu/~jano/
Semantic Web Journal: http://www.semantic-web-journal.net
Received on Friday, 26 October 2018 15:18:03 UTC

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