SIGRIC: Sistema di Gestione Rischio Chimico
A guided tour: GIS and object data bases
To support geographical selection from the map, but also to
manage all spatial data used by the models and the expert system,
an embedded GIS offers a selection of different background maps
and spatial data sets.
The most important for the modeling and evaluation functions are the
DTM (Digital Terrain Model) and the population distribution.
The GIS data and visual background must cover the entire
range of scales from the Provincial overview level
where the emergency site is selected, to the local scale
covering the immediate neighborhood of an emergency,
usually within a few kilometers.
Arbitrary zooming with an automatic switching to
higher resolution map data with increasing zooming level
is supported by the
The DTM (Digital Terrain Model) is used as a basic input data set for the
diagnostic wind field model (DWM), which in turn provides a
spatially distributed vector field for the dispersion modeling.
A range of 3D display functions support the visual analysis of the terrain,
and its effect on the atmospheric dispersion model results.
Closely related to the GIS data layers are the
these are objects like chemical plants, depots, loading stations,
airports, gas stations, but also hospitals, fire depots, police
stations etc., located in the domain. Risk Objects are georeferenced,
and play a special role either as a source of risk
(like a hazardous installation under the Seveso II Directive)
or as a resource for risk management like a hospital.
To support the user, data bases like a
hazardous chemicals data base
can be called up, inspected, and the available substance data loaded
for direct use by the expert systems inference rules as well as the
embedded simulation models.
The information combines a data base of substance properties
(numerical and symbolic values) and associated textual and graphical
information that contains, for example the substance
Material Safety Data Sheet (MSDS) in hypertext format.