The Web GIS platform Server architecture is consisted of
three layers: User Interface Layer, Application Server Layer
and Database Layer. The figure 3 shows the Service oriented
architecture of GIS-T platform.
Application Server Layer. In the application server layer, the
GIS web services, Servlet/JSP interface, GCO services that
include GML and WMS map service, and basic system
application service deployed in the J2EE server container. The
GIS function such as the zooming out and in, viewing, panning
and finding be designed as a function session bean that can be
accessed by the GIS web service, Servlet/JSP and other
Application interfaces. The application server layer is built as a
J2EE application, with several EJB modules, to provide servercentric
spatial functions to applications. Key components of
the server that implemented as EJBs are Web GIS services,
Geo-spatial functions, such as the viewing, layer selection,
editing, querying, and analysis Data Source Management.