Web Services Composition and Geographic Information - Geographical Information Systems: Trends and Technologies - page 128

This makes it compatible with all other high level protocols of the W3C
service stack (Powell 2004).
Unfortunately, due to the large number of existing geographic services
not supporting SOAP or WSDL, the integration of W3C and OGC services
is still challenging. However, as discussed in the next section, the growing
necessity to integrate the two worlds has led researchers to investigate
possible solutions that would allow the current W3C and OGC services
to communicate.
Web and OGC Services Integration
The opportunity to use the enormous amount of geographic information
accessible via OGC services within W3C services is one of main reasons
stimulating the efforts to seamlessly combine these two different worlds.
In fact, geographic community recognizes that a more complete integration
with the SOAP and WSDL protocols would allow for employing all
standards specifi ed for the W3C platform, such as those relating to security
and rights management.
To reach this aim, some issues have to be faced which cannot be solved
by a mere mechanical process meant to make a translation from one service
standard to another by simply transforming an OGC service interface
into a WSDL document. Indeed, other aspects should be considered, e.g.,
the management of the metadata returned with Capabilities documents.
In addition, it is relevant to avoid, as much as possible, both moving the
computational complexity of the whole operation to the service client, and
making any substantial changes to already existing services.
The focus of the following subsection is on a review of current solutions
presented in literature. They share, as an underlying idea, the design of a
service wrapper or a proxy meant to provide for geographic information
in a W3C compliant way, keeping the structure of existing W3C or OGC
services unchanged. Then, the INSPIRE directive is presented, which aims
at creating a common spatial data infrastructure for facilitating the sharing
of environmental information. Finally, a brief discussion about SOAP
performances is done.
An overview of current solutions
A fi rst proposal can be found in a discussion paper from OGC (Gartmann
and Schäffer 2008). In this work, the authors propose a generic approach to
equip OGC services with a SOAP binding that allows for the transformation
of any HTTP GET or POST request into a SOAP request. The proposed
solution might be used as a basis for the construction of a wrapper to
be applied to all OGC services, thus making the SOAP transformation