Visualização da relevância da informação geográfica em aplicações móveis

• Autor(a) principal: Gonçalves, Tiago José Lopes
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10451/13852
• topic: mobile devices; off-screen objects; relevance; information visualization

The use of the geographic information from mobile devices is an area that is becoming increasingly widespread and, therefore, in the last decade, there has been a growth on the development of mobile services using geographical information, like Location Based Services (LBS) or mobile geovisualization services. Despite this growth, there are still several challenges that are worth to investigate on the field of information visualization on mobile devices. The small dimension of these devices‟ screens requires filtering mechanisms to provide only the most relevant information to the user. This information is often located off-screen, increasing the user's cognitive workload to perform search tasks and making the navigational task complex. To solve the first problem several mechanisms have been proposed to select the relevant information, based on information about the context and the user's preferences. However, it does not provide any information about the relevance of points of interest located off-screen. To solve the second problem some techniques have been proposed for the signalization of off-screen objects. None of them, however, explores the relevance of those objects. This work describes and evaluates a visualization technique, called HaloDot, which combines the signalization and identification of off-screen objects with the visualization of their relevance. HaloDot uses color and transparency to express the relevance of off-screen objects. These graphical attributes were also used in other off-screen visualization techniques, which were compared with HaloDot. The results of the performed evaluation suggest that the use of the combination of colour and transparency is efficient for the representation of the relevance. Additionally, it is necessary to take into account three factors to select an off-screen visualization technique, namely: the number of existing points of interest, the proximity of the points of interest to the on-screen area and the simbology used for the representation of the points of interest.