This paper discusses the design and development of a
preference-based search tool (PBST) for tourists, operating on PDA
devices. PBSTs are decision support systems that help users in finding
the outcomes (e.g., multi-attribute products or services) that best satisfy
their needs and preferences. Our tool is specifically aimed at filtering the
amount of information about points of interest (POIs) in a geographic
area, thus supporting users in the search of the most suitable solution to
their needs (e.g., a hotel, a restaurant, a combination of POIs satisfying
a set of constraints specified by the user). We focus on the design of an
effective interface for the tool, by exploring the combination of dynamic
queries to filter POIs on a map with a visualization of the degree of
satisfaction of constraints set by the user. We also report the results
