Description
From: http://joinup.ec.europa.eu/mailman/archives/dcat_application_profile/2015-February/000123.html
Spatial coverage is specified in a variety of ways - e.g., geometries (bounding boxes), country codes, geographical names - which are usually domain-dependent. This prevents interoperability, but it is on the other side unfeasible to force the use of a single approach, since (a) this might go against existing standards and (b) a given approach may not be suitable to model the notion of location of given domains.
DCAT-AP rightly adopted a flexible approach, recommending the use of the Core Location vocabulary, and not formally excluding a priori any of the common practices. However, it might be useful to complement this with a number of best practices, that, e.g., may correspond to the different ways spatial coverage is specified in the relevant metadata standards (e.g., typically, geospatial metadata use bounding boxes, and statistical metadata NUTS).
This would be an opportunity to extend the harmonisation (and possibly interoperability) of spatial coverage.
Proposed solution
Recommend best practice for spatial coverage.
Comments
We will refer this issue to the parallel activity that work on the GeoDCAT-AP: https://joinup.ec.europa.eu/node/139283/
Out of scope for revision of the specification. May be considered for future activity.
GeoDCAT-AP (based on the INSPIRE Metadata Regulation and the ISO19115 standard) supports also the ability of specifying spatial coverage with a bounding box or with a geographic identifier. For INSPIRE Metadata records the bounding box is required and most INSPIRE metadata records do not use geographic identifiers. Therefore, it would be desirable for DCAT-AP to include both geographic identifiers and bounding boxes as non-mutually exclusive options, as is currently already the case for GeoDCAT-AP. Furthermore, GeoDCAT-AP provides a number of recommendations on the encoding of the bounding box (multiple encodings are accepted, but GML or WKT must be made available).
See also:
141755 - How to encode or represent a geographic bounding box or geometry
142997 - GeoDCAT-AP - Mapping geographic identifiers for spatial coverage
DCAT-AP already allows both named entities using controlled vocabularies and coordinates. The description of the Locations class in DCAT-AP v1.01 reads:
A spatial region or named place. It can be represented using a controlled vocabulary or with geographic coordinates. In the latter case, the use of the Core Location Vocabulary is recommended.
Proposed: to add to the sentence above:
... following the approach described in the GeoDCAT-AP specification.
This will be included in Draft 4
Usage note for class Location now reads
A spatial region or named place. It can be represented using a controlled vocabulary or with geographic coordinates. In the latter case, the use of the Core Location Vocabulary[1] is recommended, following the approach described in the GeoDCAT-AP specification[2].
[1] European Commission. Joinup. Core Location Vocabulary. https://joinup.ec.europa.eu/solution/core-location-vocabulary
[2] European Commission. Joinup. GeoDCAT-AP. https://joinup.ec.europa.eu/node/139283/