2.3. Methodology
The semiautomatic methodology herein described has been implemented
in order to carry out a quantitative analysis of the urban sprawl
process using ASTER satellite imagery and open source software. The
importance of our objective is connected with the fact that today satellite
time series and ancillary data are currently available, even free of
charge (from national and international spatial agencies) and offer a
great potential for a quantitative assessment of urban expansion; nevertheless
suitable data processing (free and open source easy to be applied
and generalized) are needed to extract and map reliable information
from space.