Design Of Composite-Symbol Representation For Landmark Buildings

As a sign of a region,landmarks are elementary component of spatial representation in a cognitive map and are of great significance for map cognition and map service.When using maps,people usually want to know the functions of landmarks,so as to make travel decisions and locate and navigate through landmark symbols.Therefore,visual features and semantic features are important components of symbol representation of landmark buildings.Research shows that users are most likely to recognize symbols whose contour shape is similar to their corresponding landmarks.At present,the representation design and method of landmark symbols on maps mainly consider visual features and functional features.However,there is a lack of general landmark symbol design that can show both the unique external features and the internal functional state of landmarks and the method that can efficiently extract the visual features of landmarks.Therefore,in order to make landmark symbols more in line with human cognitive needs,this paper comprehensively reflect the visual and functional features of landmark buildings on the map,a representation design method of composite-symbols for landmark buildings is proposed in which visual features are obtained by extracting the contours of landmark buildings through an automated method.The main work of this paper are as follows:(1)A representation design method of composite-symbols for landmark buildings is proposed in this study.Landmark symbols are decomposed into two types of morphemes including building contour characteristics,function and functional status of landmark buildings.The design concept of composite-symbols representation is proposed: landmark symbol = {contour morpheme,function type {graphic morpheme},function state {graphic morpheme}}.(2)The representation of special contour morphemes and general function morphemes are designed respectively.The contour morphemes are generated by contour line extraction based on landmark photos.The contour extraction is divided into three steps:image segmentation,contour line extraction and contour line simplification.This method can generate vectorial landmark contour morphemes to be used as the base unit of composite-symbols for landmark buildings.The representation design of the generic functional morphemes is based on people’s customary expressions and consensus,considering both shape and color factors.(3)Joining and superimposing are adopted to generate combined landmark symbols based on morphemes.Finally,a cognitive experiment of composite-symbols for landmark buildings was conducted.The experimental results show that the meaning of morphemes in the combined landmark symbols are easy to understand,and the combined form can be well accepted,which proves the effectiveness of the composite-symbols for landmark buildings representation design method proposed in this study.