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Re: UCR issue: phrasing of CRS requirement(s)

From: Andrea Perego <andrea.perego@jrc.ec.europa.eu>
Date: Thu, 21 May 2015 17:12:48 +0200
Message-id: <CAHzfgWDgiFgTP6eT7AmtG+U_kQj5ojsGUBAKKUVGQza6H5yH7w@mail.gmail.com>
To: "Svensson, Lars" <L.Svensson@dnb.de>
Cc: "Kerry.Taylor@csiro.au" <Kerry.Taylor@csiro.au>, "janowicz@ucsb.edu" <janowicz@ucsb.edu>, "Simon.Cox@csiro.au" <Simon.Cox@csiro.au>, "raphael.troncy@eurecom.fr" <raphael.troncy@eurecom.fr>, "eparsons@google.com" <eparsons@google.com>, "public-sdw-wg@w3.org" <public-sdw-wg@w3.org>
s/WGS86/WGS84/, sorry.

Andrea

On Thu, May 21, 2015 at 5:11 PM, Andrea Perego
<andrea.perego@jrc.ec.europa.eu> wrote:
> On Thu, May 21, 2015 at 5:05 PM, Svensson, Lars <L.Svensson@dnb.de> wrote:
>> Kerry,
>>
>> On Thursday, May 21, 2015 4:23 PM Kerry.Taylor@csiro.au wrote:
>>
>>> RE axis order,
>>> I know there is a great deal of frustrated experience  and errors with this.
>>> The thing is, with ontologies like Raphael's and with "linked data" (I mean RDF
>>> instance data in any of its forms, including JSON-LD),
>>> normally ordering is irrelevant as a description for each value is provided
>>> (commonly called "self describing'). E.G.  Have a look at "geo" I pointed at
>>> before. http://www.w3.org/2003/01/geo/wgs84_pos
>>
>> wgs84_pos et al. are fine as long as you just deal with point coordinates. As soon as you start talking about bounding boxes etc. it turns _way_ more complicated. Even in simple settings we need to describe more than points.
>
> I agree with Lars. The approach used in the WGS86 lat/long vocabulary
> is not scalable for complex geometries. And, in any case, many people
> will keep using literals. BTW, schema.org uses literals for "shapes"
> (http://schema.org/GeoShape) and longitude, latitude, and elevation
> for points (http://schema.org/GeoCoordinates).
>
> For this reason, it would be useful to find a way to make explicit the
> axis order used in geometry literals (as in the example provided by
> Peter), without the need of processing the corresponding CRS
> description.
>
> I also think that the axis order issue is very much related to the
> notion of "spatial" data as we are using it (i.e., not only
> geo-spatial data). Non-geo people will keep on reading coordinates as
> lon / lat, because this is the order used in a cartesian reference
> system, and this is also the order used by communities dealing with
> spatial data (e.g., computer graphics).
>
> A possible option would be to require the specification of the axis
> order only is it is lat / lon (lon / lat), implying that the default
> should be lon / lat (lat / lon).
>
> Andrea



-- 
Andrea Perego, Ph.D.
Scientific / Technical Project Officer
European Commission DG JRC
Institute for Environment & Sustainability
Unit H06 - Digital Earth & Reference Data
Via E. Fermi, 2749 - TP 262
21027 Ispra VA, Italy

https://ec.europa.eu/jrc/

----
The views expressed are purely those of the writer and may
not in any circumstances be regarded as stating an official
position of the European Commission.
Received on Thursday, 21 May 2015 15:13:37 UTC

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