# RE: How to represent geographic coordinates for maps

```Hi,

I was just about to type the same as Konrad. The coordinate representation would be very hard to do anything useful with. You could possibly look at using:

http://www.w3.org/2005/Incubator/geo/XGR-geo-20071023/

Maybe use georss:Box. Alternative (and probably more future proof) look at GeoSPARQL and encode the geometry that way. Not too many GeoSPARQL implementations around at the moment though.

John

Dr John Goodwin
Principal Scientist
Research, Ordnance Survey
Adanac Drive, SOUTHAMPTON, United Kingdom, SO16 0AS
Phone: +44 (0) 23 8005 5761
www.ordnancesurvey.co.uk | john.goodwin@ordnancesurvey.co.uk

-----Original Message-----
Sent: 12 July 2013 10:51
To: public-geosemweb@w3.org
Subject: Re: How to represent geographic coordinates for maps

Hi Lars,

To question 3: First, I think that depending on the projection and scale, a rectangle on a map is not/only nearly representable by a rectangle in geocoordinates.
Furthermore, the representation you chose (""W 13' - E 49' / N 45°58' - N 45°33'""") is not very easily machine-readable because you code a rectangle into a single literal and also use a coordinate notation that needs additional parsing.
Maybe polygons like the ones used in LinkedGeoData would be helpful? A

Regards,

On 12.07.2013 11:14, Svensson, Lars wrote:
> All,
>
> At the German National Library we are currently looking into how to represent coordinates for maps and we need some advice on which representation would be most useful for the community.
>
> While looking at publishing coordinates for places in the library authority data, we also started looking at how to represent the geographic extent of maps. I came across three vocabularies that could be useful for that:
> 1) the (library-specific?) properties scale:
> http://rdvocab.info/Elements/scale, projection:
> http://rdvocab.info/Elements/projectionOfCartographicContent and
> coordinates:
> http://rdvocab.info/Elements/coordinatesOfCartographicContent from RDA
> (Resource Description and Access)
> 2) the properties from wgs84_pos
> 3) the properties from geosparql
>
> If I have understood things correctly, only the RDA ones are applicable directly for a map, whereas wgs84 and geosparql really are about places and not about maps, so that you would need to introduce a level of indirection to use them directly for maps. A (made-up) example:
>
> my:resource a ex:Map ;
>         dc:title "The Marauder's Map" ;
>         rdvocab:coordinatesOfCartographicContent """W 13' - E 49' / N 45°58' - N 45°33'""" .
>
> my:resource a ex:Map ;
>         dc:title "The Marauder's Map" ;
>         dct:coverage [ a wgs84_pos:SpatialThing ;
>                 wgs84_pos:lat_long """ W 13' - E 49' / N 45°58' - N 45°33'""" ;
>                 .
>         ] .
>
> So my three questions:
> 1) Is my interpretation of the use of wgs84 for maps correct?
> 2) Are coordinates for maps of any use at all to this community?
> 3) (If the answer to 2) is yes): which representation would be the best for your use cases?
>
> Thanks in advance for any insight,
>
> Lars
>
> ***Lesen. Hören. Wissen. Deutsche Nationalbibliothek*** ***Reading.
> Listening. Understanding. German National Library***
>

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