International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004 
The geocomputation process step will derive information and/or 
knowledge from a set of archived objects through a set of 
domain-specific geospatial services. If a user requests a geo- 
object not ready available in archives, significant. domain 
knowledge is needed to derive the object. For example, a 
military analyst is doing the battlefield traversability study. The 
analyst may ask the intelligent geospatial system which areas in 
the battlefield are traversable to a specific type of military 
vehicles if there are rainfalls in the next three days. To answer 
such kind of “what 1P” questions automatically by a geospatial 
information system requires the system to have the capability to 
access to all available source data and all required service 
modules. It also requires the system to have significant amount 
of domain knowledge and modeling capabilities (intelligence) 
for automatically constructing and executing a geospatial 
process models (geo-tree). 
All other three technical questions are also concerned by OGC 
web services, the semantic Grid services, and Semantic Web 
communities. Therefore, technologies, especially those 
developed by OGC web service initiatives, should be tested in 
the realistic data environment. In addition, there has been work 
in the Semantic Web community to apply ontology ideas 
developed in the AI community to various aspects of Web 
Services and Web information search and manipulation. The 
goal of the emerging Semantic web services is to provide the 
mechanisms to organize the information and services so that 
human queries may be correctly structured for the available 
application services (the model components and data) in order 
to “automatically” build workflows for specific problems. That 
is, automatically determine the correct relationships between 
available and characterized data and services to generate the 
process models (geo-trees) and convert them to executable 
workflows to provide the “answers’ to “what if” questions. 
From this point of view, research on distributed geospatial 
service shares the same goal as the semantic web services. The 
only difference is our research will deal with geospatial 
problems in particular. 
The approach in Semantic web is to work with the Artificial 
Intelligence community to provide a set of layered extensions to 
XML in order to build up to an ontology language and tools. A 
set of candidate technologies includes Resource Description 
Framework (RDF), Resource Description Framework Schema 
(RDFS), and Web Ontology Language (OWL) (W3C 2004). 
The development in the semantic web could substantially 
enhance the automatic knowledge discovery from multi-source 
diverse geospatial data and information. 
9. CONCLUSIONS 
The geospatial information and knowledge are valuable to the 
daily socio-economic activities. The ready availability of and 
easy access to geospatial information and knowledge are the 
keys for making the geospatial information the mainstream 
information. The approach and system presented in this paper 
for automated information extraction and knowledge discovery 
under the interoperable distributed web service framework are 
very promising although significant challenges on the full 
automation of geospatial information extraction and knowledge 
discovery still exist. Although prototype systems built on this 
service framework, such as NWGISS and GeoBrain, has shown 
the significant improvement on users's discovery, access, and 
uses of geospatial data, information, and knowledge for their 
applications, many other issues, such as scalability, security, 
and reliability, need to be further investigated. 
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