W3C home > Mailing lists > Public > public-lod@w3.org > June 2010

Re: URI's for Geogrid like Resource

From: Sean Gillies <sean.gillies@gmail.com>
Date: Thu, 17 Jun 2010 09:57:13 +0200
Message-ID: <AANLkTin2o_T_4lpRgtggqMv2LmFPVXSvacVYxUJJozg5@mail.gmail.com>
To: "public-lod@w3.org" <public-lod@w3.org>
Peter,

geo: URIs are a good fit for geographic axioms such as the points in our
shared, global coordinate reference systems. IMO, we shouldn't be encoding
non-axiomatic concepts like application-specific regional partitions (grids)
into geo: URIs and should use http: URIs.

I'm working in partitioned space in a project and have realized that if I
distinguish between a spatial object and its location and use predicates
from 9IM or RCC, I can take advantage of a large field of knowledge in
qualitative spatial reasoning and handle change in location over time. For
example, instead of

  Species_A expectedIn GridCell_42

model

  Range(Species_A) hasLocation X
  X partiallyOverlaps GridCell_42

There's not a lot of qualitative spatial reasoning tools out there, but
there is abundant theory and guidance on what can and can't be reasoned.
This sort of model for species range also seems to align well with
conventional GIS vector and raster models.

Cheers,

--
Sean

On Mon, Jun 14, 2010 at 10:30 PM, Peter DeVries <pete.devries@gmail.com>wrote:

> Hi Søren,
>
> People will correct me if I am wrong but I think that rdf:Bag causes
> problems with SPARQL queries, but I like what you are suggesting and it may
> be that there is some other way to get this goal
> achieved. In the RDF example, I think I have the geonames URI for the
> Country "US". This then tags this geogrid as being in the US.
>
> The difference between this an other approaches is that each box is
> "square" and has the same area. Solutions that create grids that are based
> on degrees will get more rectangular the farther that you get from the
> equator. The nearly equal area of this approach will be helpful for species
> or individuals / area.
>
> I kind of like the idea of keeping the extent in the URI. If you start
> making geogrids of 1km x 1km as regular resources you will need a lot of RDF
> just to cover the planet. It would seem to be a big
> RAM commitment for your triple store. Having the extent included in the URI
> means that supporting triple stores would know how to interpret all of them.
> This way I just need to make statements about
> the geogrids for which I have records, not the entire surface of the
> planet.
>
> - Pete
>
> On Mon, Jun 14, 2010 at 7:30 AM, Søren Roug <Soren.Roug@eea.europa.eu>wrote:
>
>>  I doubt that encoding the geospatial extent into the URI is a good idea.
>> It would be preferable to add a bounding box property to existing resources.
>> If you go to Wisconsin in GeoNames (
>> http://linkeddata.uriburner.com/about/html/http/sws.geonames.org/5279468/)
>> you'll see a "geo:geometry" property. It has the limitation that it can only
>> handle points. But you could have an x:boundedBy property that takes four
>> values. West, South, East, North.
>>
>>
>>
>> Now, this matches your need for a geogrid URI, and it is quite easy to
>> convert to KML. But as soon as you try to put a bounding box around USA, you
>> run into problems with Hawaii and Alaska. My proposal allows you to have
>> several bounding boxes inside an <rdf:Bag> or by just repeating the
>> property.
>>
>>
>>
>> Best regards,
>>
>> Søren Roug
>>
>>
>>
>>
>>
>>
>>
>> *From:* public-lod-request@w3.org [mailto:public-lod-request@w3.org] *On
>> Behalf Of *Peter DeVries
>> *Sent:* 11 June 2010 17:20
>> *To:* public-lod@w3.org
>> *Subject:* URI's for Geogrid like Resource
>>
>>
>>
>> Hi LOD'ers,
>>
>>
>>
>> In the GeoSpecies data set I have a predicate isExpectedIn.
>>
>>
>>
>> This is used to state that a given species is expected in a geographical
>> area.
>>
>>
>>
>> Most of the time I use the geonames features as the object
>>
>>
>>
>> So <
>> http://linkeddata.uriburner.com/about/html/http/lod.geospecies.org/ses/mCcSp>
>>
>> http://lod.geospecies.org/ses/mCcSp<http://linkeddata.uriburner.com/about/html/http/lod.geospecies.org/ses/mCcSp>
>>
>> geospecies:isExpectedIn<http://linkeddata.uriburner.com/about/html/http/rdf.geospecies.org/ont/geospecies%01isExpectedIn>
>>
>> §  http://sws.geonames.org/6255149/<http://linkeddata.uriburner.com/about/html/http/sws.geonames.org/6255149/>
>>
>> §  http://sws.geonames.org/5279468/<http://linkeddata.uriburner.com/about/html/http/sws.geonames.org/5279468/>
>>
>> §  http://sws.geonames.org/4862182/<http://linkeddata.uriburner.com/about/html/http/sws.geonames.org/4862182/>
>>
>> §  http://sws.geonames.org/5037779/<http://linkeddata.uriburner.com/about/html/http/sws.geonames.org/5037779/>
>>
>> §  http://sws.geonames.org/5001836/<http://linkeddata.uriburner.com/about/html/http/sws.geonames.org/5001836/>
>>
>> I also do the reverse link so you can query what species are in what
>> geonames feature
>>
>>
>>
>>
>>
>> <!-- Wisconsin State Link Out -->
>>
>>   <geospecies:State rdf:about="http://sws.geonames.org/5279468/">
>>
>>     <geospecies:hasExpectationOf rdf:resource="http://lod.geospecies.org/ses/mCcSp"/>
>>
>>   </geospecies:State>
>>
>>  At present this just get's me to county, and I have always wanted to get
>> something that was more uniform and global.
>>
>>
>>
>> This would need URI's that are of a grid equally sized polygons that are
>> either equal in X, Y by either decimal degrees or meters.
>>
>>
>>
>> I marked up this example, that is a one tenth decimal degree by 1 tenth
>> decimal degree. It is rectangular in actual distance (meters/kilometers)
>>
>>
>>
>> http://lod.taxonconcept.org/examples/geogrid/10/N93d0_37d1_W93d0_37d1.html
>>
>>
>>
>> http://lod.taxonconcept.org/examples/geogrid/10/N93d0_37d1_W93d0_37d1.rdf
>>
>>
>>
>> What I am wondering is, is there already an existing set of URI's that do
>> the same sort of thing?
>>
>>
>>
>> Has anyone been able to create valid RDFa that also works with GoogleMaps?
>>
>>
>>
>> Thanks!
>>
>>
>>
>> - Pete
>>
>>
>>
>>
>>
>>
>> ----------------------------------------------------------------
>> Pete DeVries
>> Department of Entomology
>> University of Wisconsin - Madison
>> 445 Russell Laboratories
>> 1630 Linden Drive
>> Madison, WI 53706
>> GeoSpecies Knowledge Base
>> About the GeoSpecies Knowledge Base
>> ------------------------------------------------------------
>>
>
>
>
> --
> ----------------------------------------------------------------
> Pete DeVries
> Department of Entomology
> University of Wisconsin - Madison
> 445 Russell Laboratories
> 1630 Linden Drive
> Madison, WI 53706
> GeoSpecies Knowledge Base
> About the GeoSpecies Knowledge Base
> ------------------------------------------------------------
>



-- 
Sean Gillies
Programmer
Institute for the Study of the Ancient World
New York University
Received on Thursday, 17 June 2010 07:57:48 UTC

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