DecernsSDSS is web application build according to Java EE 5 specifications.
It has three tier architecture which is architecture in which presentation, the application processing
and the data management are logically separate processes.
The brief description of the each level of DecernsSDSS is below:
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Presentation tier implements user interface.
DecernsSDSS user interface allows performing all the operations connected
with SDSS project creation or loading, implementation of GIS and/or MCDA functions,
methods and tools, preparation of the output forms and project saving.
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Logic tier coordinates the application, processes commands, including various functions and logic transitions, and performs calculations.
It also moves and processes data between the two surrounding layers. The main components of SDSS in this layer are GIS - subsystem,
MCDA - subsystem, and models integration components, as well as different modules for management of the created projects,
map manipulation, and administering the system.
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Data tier contains data in database and xml files and functions for retrieving the necessary data/information.
XML files are used for storing mcda models, map legends and spatial alternatives.
DBMS PostgreSQL 8 is used for managing user projects, map data (features and attributes), user groups, user accounts, system settings.
Functions of PostGIS which is GIS extension of PostgreSQL are used to perform some spatial operations (buffering and overlay of vector layers).