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Use Case ID29 (Modeling spatial coverage)

From: <andrea.perego@ec.europa.eu>
Date: Fri, 7 Jul 2017 17:26:25 +0000
To: <public-dxwg-wg@w3.org>
Message-ID: <EDFF15E839F79242AA55B1468C63DDA901FB93C8@S-DC-ESTG02-J.net1.cec.eu.int>
Dear colleagues,

As promised during the last call, I'm providing some more details on the rationale behind the use case concerning spatial coverage [1]. 

1. The use case is basically reporting one of the issues identified by the GeoDCAT-AP WG in the use of DCAT for the representation of geospatial metadata, 

The standard used for geospatial metadata is ISO 19115, where spatial coverage can be specified in 2 different ways:
- a geographical name (which denotes a geographic area)
- geographic coordinates - as a bounding box or a polygon

As said in the use case, DCAT provides an example on how to specify spatial coverage with a geographical name (by using a Geonames URI), but not with geographic coordinates. The lack of guidance on this in DCAT has resulted in a variety of not compatible approaches in existing metadata records, which prevents interoperability (and, as a consequence, this information cannot be consistently used for discovery purposes). GeoDCAT-AP addresses this issue with the solution illustrated in the use case.

2. As explained in point (1), the use of arbitrary geometries to denote spatial coverage is reflecting existing practices and requirements in the geospatial domain, but which are not necessarily specific to it - e.g., DataCite supports geometries as well. The rationale behind using geometries instead of geographical names is multifold, but (over-simplifying) it is basically related to the need of denoting an arbitrary geographic area, which may not necessary match a geographical name. Examples include satellite images and data from sensors.

3. Using geometries for spatial search is already supported in data catalogues (not only geospatial ones, as GeoNetwork, but also general-purpose catalogue platforms as CKAN). Moreover, the majority of triple stores supports spatial queries that can be used to identify datasets about an arbitrary region, specified with a geometry. So, geometries are already being used for discovery / filtering purposes.

I'll revise the use case to make these motivations clear.



Andrea Perego, Ph.D.
Scientific / Technical Project Officer
European Commission DG JRC
Directorate B - Growth and Innovation
Unit B6 - Digital Economy
Via E. Fermi, 2749 - TP 262
21027 Ispra VA, Italy


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 Friday, 7 July 2017 17:26:56 UTC

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