Designing a personal guidance system to aid navigation without sight: progress on the GIS component

This paper reports on progress towards the development of a personal guidance system for a blind navigator. The system is being developed in light of the unique problems facing the blind traveller, which are discussed first. The system consists of four modules: a locator unit, a detailed spatial database, an algorithm for path selection and a user interface. Suggestions are offered for alternative ways of handling the locator problem using a global positioning system or a database query system. The nature of the geographic information system (GIs) to be used as a host for the database is discussed, followed by brief statement of the criteria for choosing an algorithm for path selection and suggestions on types of user interfaces best suited to the system. A report on a pilot-study G I s is presented. Special problems of database and system design are highlighted. 1. Purpose Our purpose in this paper is to present a conceptual model of a personal guidance system (PGS) designed to assist vision-impaired travellers to move more freely about their environment than would otherwise be the case. We also report on work in progress related to designing and testing components of such a system. In particular, we discuss problems of determining position, general orientation and heading. These questions are examined i n the context of building a geographic information system (GIs) containing information relevant for travel without vision. We also comment on the possible characteristics of a path-finding algorithm for travel and ways of transmitting information to a vision-impaired traveller. Our conceptual model underlits ongoing multi-disciplinary research at the University of California -Santa Barbara (UCSB) that focuses on navigation without sight. This research project has, as its ultimate goa1,the development of a PGS with several components. As described by Loomis (1985), these components included a spatial database (currently .conceived of as a GIs), a module for determining a navigator's position and a user interface for displaying map information to the traveller. To these components we have added a route-planning module and a querying ('where am I?') system that aids the traveller in determining location. In this paper, emphasis is given to the GIs-related component and the associated querying system. Our larger research project has examined human ability to navigate without vision. This work is continued by addressing questions of integrating the cognitive and movement processes associated with the estimation and reproduction of distance and turn angle, retracing routes and short-cutting. Ongoing basic research includes examining the effect of en-route changes of destination, the development of configurational understanding after rotation or translation of location, scale effects in spatial 0269-3798191 S340