Dear Roger,
On 11 May 2010, at 09:42, Roger Hyam wrote:
Hi Rod,
What we were talking about the other days (and indeed in the corridors of last years TDWG) is the need for a polygon repository. It would be really nice is someone (GBIF?) ran a geoserver that you could register polygons with and once registered they were given a nice URI and became semantically linkable with their metadata in RDF. This would obviously need long term commitment. I'd do it if I had funding....
Within PESI we were talking about it in terms of the TDWG regions and possibly extending them to maritime regions but really there are endless lists of polygons - like the IUCN protected areas or how about the oil spill effected areas etc etc.
This would be useful, it could also contain polygons of species distributions (say from RedList).
This probably doesn't answer your question!
Another approach would be to have a literal property with a value that is a Well-known text of the distribution.
http://en.wikipedia.org/wiki/Well-known_text
This is the approach taken by DwC.
You could use the DwC property or make one up such as rod:hasFootprint="POLYGON ((10 20, 11 20, 11 21, 10 21, 10 20))"
That's what I'm using at the moment, dwc:footprintWKT (as well as another vocabulary to describe the points). Just toggle the display at http://bioguid.info/csquare/ , or use a linked data client to get the RDF.
You can use multipoint and other ways to describe the distribution data with well known text.
I am sure there are semantic and geospatial people who would object to almost any approach!
Yep. One thing I like about c-squares is that the URI is computable from a pair of co-ordinates. Given a lat,long pair you can compute the c-square. This makes it possible to do basic search and indexing on the URI, plus you don't need to search a service to construct the URI.
For larger, more complex polygons I guess we'd loose this (lots of ways to represent a polygon, fewer chances of identity or containment).
Might be fun to think about this, as I'd like to mash up GBIF squares, GenBank points, and IUCN ploygons...
Regards
Rod
Good luck
Roger
On 10 May 2010, at 16:11, Roderic Page wrote:
Dear All,
I'm interested in referring to a GBIF distribution map in RDF, and am having fun figuring out how to do it. One way is to use a c-squares- based URI, see http://iphylo.blogspot.com/2010/05/referring-to-one-degree-s quare-in-rdf.html (http://tinyurl.com/33ba4kt).
The idea is that each 1° × 1° square in a GBIF map has it's own c- squares-based URI, e.g. http://bioguid.info/csquare:3317:364 , and hence a distribution would be a list of these URIs (perhaps with the number of records from each square).
Any thoughts on this approach, and whether we have an existing vocabulary to describe these relationships?
Regards
Rod
Roderic Page Professor of Taxonomy DEEB, FBLS Graham Kerr Building University of Glasgow Glasgow G12 8QQ, UK
Email: r.page@bio.gla.ac.uk Tel: +44 141 330 4778 Fax: +44 141 330 2792 AIM: rodpage1962@aim.com Facebook: http://www.facebook.com/profile.php?id=1112517192 Twitter: http://twitter.com/rdmpage Blog: http://iphylo.blogspot.com Home page: http://taxonomy.zoology.gla.ac.uk/rod/rod.html
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--------------------------------------------------------- Roderic Page Professor of Taxonomy DEEB, FBLS Graham Kerr Building University of Glasgow Glasgow G12 8QQ, UK
Email: r.page@bio.gla.ac.uk Tel: +44 141 330 4778 Fax: +44 141 330 2792 AIM: rodpage1962@aim.com Facebook: http://www.facebook.com/profile.php?id=1112517192 Twitter: http://twitter.com/rdmpage Blog: http://iphylo.blogspot.com Home page: http://taxonomy.zoology.gla.ac.uk/rod/rod.html