This paper presents an assessment of the effectiveness of using Personal Data Assistants (PDA) equipped with Geographic Information System (GIS) and Global Positioning System (GPS) in field data collection of tourist movement. On-site questionnaire survey and GPS tracking of the leisurely walk of selective groups of park visitors were conducted between August 2005 and January 2006 at various entry points to the Pokfulam Country Park in Hong Kong. The results were examined by means of mapping, 3D visualization, and statistical analyses. Our results indicated that the time of survey and spatial locations influenced the reception of GPS signals. Environmental factors such as terrain, built structures, and tree canopies played an important role in the positioning accuracy. We managed to illustrate a workable methodology for tracking the flow of tourists and made recommendations on possible uses of such a practice in tourism planning and management.