1. A data input subsystem that collects and
preprocesses spatial data from various sources.
This subsystem is also largely responsible for
the transformation of different types of spatial
data(i.e. from isoclines symbols on a
topographic map to point elevations inside the
GIS) [1]
2. A data storage and retrial subsystem that
organizes the spatial data in a manner that
allows retrieval, updating, and editing.
3. A data manipulation and analysis subsystem
that performs tasks on the data, aggregates and
disaggregates, estimates parameters and
constraints, and performs modeling functions.