An agreed spatial ontology

Hello,

I meant to send this message earlier, but a bout of illness got the better
of me...

At the F2F meeting in Amersfoort we talked about the spatial ontology that
should be included in the Spatial Data on the Web Best Practices according
to our charter <https://www.w3.org/2015/spatial/charter>. It says that the
deliverable will include *“an agreed spatial ontology conformant to the ISO
19107 abstract model and based on existing available ontologies such as
GeoSPARQL, NeoGeo and the ISA Core Location vocabulary”*.

We talked about the possibility of really trying to make that happen. The
discussion did not reach a clear conclusion and it was decided to park the
subject. With this message I hope we can revisit the subject because I
think it is very important and therefore should not be parked too long.

I think a good spatial ontology could help in many different areas, such as:

   - Providing a bridge, or common ground between geographical and
   non-geographical spatial data.
   - Provide a foundation for harmonization of the many different geometry
   encodings that exist today.
   - Provide basic semantics for the concept of a reference system for
   spatial coordinates.
   - Provide a link between W3C standards and OGC standards.
   - Definition of a basic datatype, or basic datatypes for geometry.
   - Agree on how geometry and real world objects are related and how
   different versions of geometries for a single real world object can be
   distinguished. For example, it makes sense to publish different geometric
   representations of a spatial object that can be used for different
   purposes. The same object could be modelled as a point, a 2D polygon or a
   3D polygon. The polygons could have different versions with different
   resolutions (generalisation levels). And all those different geometries
   could be published with different coordinate reference systems. Regardless
   of geometry encoding, we need agreement on how to relate different
   geometries with different characteristics to an object/resource.

I think a basic shared model of geometry on the Web could help solve a
multitude of current and future problems. Sure, it will be quite a task,
but it could very well be worth the effort. Of course we can decide not to
do it, for any set of reasons, but I do think we owe it to the world we try
to serve to at least give it some serious consideration. Also we could
consider taking just a few steps in the right direction, without any
promises that we will come up with the perfect universal ontology. An
option could also be to look specifically at GeoSPARQL, as an ontology that
already is a merger of OGC and W3C standards, see to what extent it
addresses our requirements, and what could be done to make it the single
basic universal spatial ontology that would be so great to have.

Regards,
Frans