Harry Chen of Image Matters LLC gave an invited lecture in my semantic web class yesterday. His topic was An introduction to Geospatial Semantic Web technology.
This presentation covers key issues related to Geospatial Semantic Web: (1) extracting hidden knowledge from unstructured and structured data, (2) knowledge fusion over heterogeneous data sources, (3) ontology sharing and (4) building user-friendly Semantic Web applications. It also describes state-of-the-art technologies that attempt to solve these problems. This discussion covers upper-case Semantic Web vs. lower-case semantic web, GeoRSS, W3C Geo ontology, GML, Flickr machine tags, geonames and Google Maps mashups.
I was away on travel, but am familiar with the work, which is great, as are his slides, which are available here. Harry runs the Geospatial Semantic Web Blog which is an excellent resource on the topic.