Symbol-based Simplification with Fuzzy Logic Approach on Mobile Devices

Recent developments of GSM technology enable new applications in distributed GIS and LBS so as to provide more relevant active service to the mobile user. Specifically, the visualization of the spatial data is very important for mobile devices that have limited display capacity. The visualization problems are mostly dealt with generalization algorithms such as displacement, simplification and aggregation in order to obtain appropriate cartographic design. In this paper, a new simplification method that allows an adapted visualization is proposed. According to the proposed model, instead of scaled polygonal spatial representation, symbolizations are used for the visualization. In theory, a spatial object is replaced with a symbol in order to make user’s perception easier in the restricted screen of the mobile devices. Obtaining an appropriate icon size for a spatial object is very complex case because of the various parameters of the determination of the symbolization. Besides, there is also a vagueness of the situation in the visualization. Solution, therefore, needs a fuzzy logic approach so as to obtain coherent results. Symbol dimensions are calculated automatically with fuzzy inference depending on both the display resolution and the covered area of the polygon. A technological architecture of the distributed GIS has been designed to realize cartographic generalization on the mobile phones. Finally, adaption has been provided for the each spatial object separately according to the display resolution capacity of the mobile device and the size of the spatial object.