Re: Best Practice for encoding spatial coverage

indeed, confirming this (Frans, you already had a feeling in that direction):
the envelope defines a bounding box whose coordinates are expressed in the CRS
also referenced in the envelope. Here is a simple OGC coverage example (in XML,
but easy to translate into RDF, JSON, etc), just FYI:

<gml:Envelope srsName=" http://www.opengis.net/def/EPSG/0/4326“
            axisLabels="Lat Long" uomLabels="deg deg" srsDimension=“2">
            <gml:lowerCorner>1 2</gml:lowerCorner>
            <gml:upperCorner>3 4</gml:upperCorner>
</gml:Envelope>

-Peter

On 06/17/15 12:09, Simon.Cox@csiro.au wrote:
> Frans -
> You really don't have to make this up afresh.
> ISO 19107 defines a property 'envelope' for any geometry, with a value of type
> GM_Envelope, which has a lower and upper corner, whose values are points.
> ISO 19123 defines a property 'domain extent' for any coverage, with a value of
> type EX_Extent, which is a bit more complex (defined in ISO 19115).
> There is no standard property for the corresponding thing for a generic
> feature, but 'bounding box' is a common name.
>
> Simon
>
> Caveat lector - Sent from a tablet using TouchDown*
>  
> *
> --------------------------------------------------------------------------------
> *From:* Frans Knibbe
> *Sent:* Wednesday, 17 June 2015 9:53:42 AM
> *To:* SDW WG Public List
> *Subject:* Best Practice for encoding spatial coverage
>
> Hello all,
>
> Is it OK to try to venture in to the domain of best practices already? I
> wonder if we can try our hands at the following issue:
>
> I have just had a talk with a web developer on the best way of making the
> extent of a spatial data set known, in a Linked Data context. It is useful to
> know the spatial extent of a data set because that way a map can be zoomed in
> on the right patch of Earth. 
>
> I think an obvious predicate for making the extent known is dcterms:spatial
> <http://dublincore.org/documents/dcmi-terms/#terms-spatial> (Spatial
> Coverage). That should point to a dcterms:Location
> <http://dublincore.org/documents/2012/06/14/dcmi-terms/?v=terms#terms-Location>,
> which can have a geometry. So an option would be to encode the extent as a WKT
> polygon, according to GeoSPARQL semantics. But that would not be the most
> webdeveloper-friendly way of making the extent known.  The usual way of
> setting a map extent involves knowing the minimum and maximum values for X and
> Y. So a question is: what would be the best way to publish the minimum and
> maximum X and Y? There are usable vocabularies for publishing point
> coordinates, so one could think of recommending to publish two points (lower
> left corner and upper right corner). Perhaps there are standard vocabularies
> available that define the concepts of 'minimum' and 'maximum' and 'x' and 'y'?
>
> I should note that this issue relates to the Spatial metadata requirement
> <http://w3c.github.io/sdw/UseCases/SDWUseCasesAndRequirements.html#SpatialMetadata>. 
>
>
> Greetings,
> Frans
>
>
>
> -- 
> Frans Knibbe
> Geodan
> President Kennedylaan 1
> 1079 MB Amsterdam (NL)
>
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> www.geodan.nl <http://www.geodan.nl>
> disclaimer <http://www.geodan.nl/disclaimer>
>

-- 
Dr. Peter Baumann
 - Professor of Computer Science, Jacobs University Bremen
   www.faculty.jacobs-university.de/pbaumann
   mail: p.baumann@jacobs-university.de
   tel: +49-421-200-3178, fax: +49-421-200-493178
 - Executive Director, rasdaman GmbH Bremen (HRB 26793)
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