Geospatial Semantic Web Blog

The W3C Geospatial Incubator Group recently published two reports on geospatial vocabularies and ontologies. The announcement came through the W3C Semantic Web News:

The final reports of the W3C Geospatial Incubator Group has just been published: Geospatial Vocabulary and Geospatial Ontologies. The first document also includes a reference to a GeoOWL ontology that relies on other, existing vocabularies (like GeoRSS or GML). The second document gives an overview of some other, existing ontologies in the area.

These two documents provide a good overview of existing vocabularies and ontologies. Use cases of geospatial ontologies are described in the Geospatial Vocabulary document. Based on my reading, the group has reached an agreement on a model for representing geometry objects (points, lines, polygons, etc.) but not yet on a model for expressing geospatial relationships (within, touches, overlaps, etc.).

GeoRSS seems to play an influential role in the described model. This is a good sign. To application developers, ontology construction is a means to an end. RSS and GeoRSS extensions enabled the creation of many useful applications. Building on these standards will encourage a broader community to embrace a Geospatial Wemantic Web.

Speaking at a conference hosted by Ordance Survey, Sir Tim Berners-Lee explains how Semantic Web technology can advance GIS information sharing and interoperability. The detail of his speech is covered in this ZDNet article.

Few items mentioned in the article worth our attention.

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The Web has made people smart. It allows the everyday people to discover, publish, and share information. The Web is a profound technology not only because it allows the display of pretty pictures and the layout of well-formatted texts, but also because it’s a technology that everyone can use.

Like the Web technology, geospatial technology should also be developed for the everyday people. The key is to help everyday people, not just few groups of elite techno-geeks, to do more by doing less.

So, what’re those useful geospatial technologies? Many speakers at the Where 2.0 conference have talked about them.

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Geospatial ontologies are formal representations of geographical concepts and relations. At the Networking Geospatial Information Technology, Jerry Hobbs of ISI gave an interesting presentation on understanding and developing geospatial ontologies.

His thesis is that in order to develop geospatial semantic web applications, we must first develop a core theory of geospatial and other spatial representation and reasoning. In particular, he discussed ontology development from a natural language perspective — e.g., how do we model queries such as “How long is chile?”, “How large is N. Korea?”, “How far is LA from Washington DC, as the crow flies?”

He also brought up a lot of interesting issues such as scales and half orders of magnitude.

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These days it seems like everyone has a camera phone, and everyone posts photos on Flickr. Wouldn’t it be great if photos taken on your camera phone can be automatically tagged with location information and then published onto Flickr?

Check out ZoneTag.

ZoneTag can automatically tag your photos with the location, based on the cell tower, in which they were taken. ZoneTag is known to work on 6620, 6670, 6680, 6681, 6682, 7610 models, and it is likely to work on 3230, 6630, 6260 as well

Of course, it has some limitation.

The location of the cell tower is not known until our user community updates the city, state, or zip code of their photos on Flickr.

I don’t have a Symbian phone, so I can’t try it out. If anyone has a chance to play with this software, please let me know what you think.

OGC (Open Geospatial Consortium) published two online multimedia demonstrations documenting the milestones achieved in the OGC Web Services Phase 3 Initiative, (OWS-3). The goal of OWS initiatives is to promote and demonstrate the use of various OGC open geospatial specifications.

In OWS-3, participants worked in the following areas:

• Common Architecture
• Sensor Web Enablement (SWE)
• Geo-Decision Support Services (GeoDSS)
• Geo-Digital Rights Management (GeoDRM)
• Open Location Services (OpenLS)

I watched the video, and I think it’s well made. The demo also gives a good overview of what OGC does and the importance of data interoperability.

An official announcement from OGC is available online.

Jeff Thurston at Vector One writes,

“I think interoperability is not THE issue. The issue in the GIS and geospatial arena is structural barriers internal to enterprises. It is all about breaking the barriers between people.

We need to get back to the basics, discussing what it is we want to do with the many high quality tools we have created across this industry and how they can really be used - and - changing the structural processes in organizations to make it happen.”

I think interoperability is a problem, at least from the knowledge integration point of view. Organizations have invested a lot of time and money to collect information. Different information collected over the years often is not stored in the same representation format.

Though his suggestion makes great sense, I doubt that it’s the most cost-effective solution. It’s not always economical to reconsolidate datastores just because we want different schemas to align and use shared vocabularies. NGA people told me once, “reconsolidation is expensive”.

I believe semantic interoperability is a better solution.

Geospatial Semantic Web

The most value asset in a GIS system is data. Without data, a GIS system is like a computer system with the best peripherals but only with an empty hard drive — it’s useless. If data is so important, it is necessary for us to understand the role of data in the future GIS systems — i.e., the Geospatial Semantic Web.

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