tailieunhanh - Dynamic and Mobile GIS: Investigating Changes in Space and Time - Chapter 8

Ba chương hình thành "Phần III - Hiển thị và trực quan" luận án của 'GIS động và điện thoại di động: Điều tra thay đổi trong không gian và thời gian "xem xét những thách thức của trực quan Trong thời hạn Các ràng buộc của GIS di động, đặc biệt là màn hình nhỏ của một PDA điển hình, mục tiêu aussi chỉ có những hạn chế của việc sử dụng GPS như là một hệ thống định vị | Part III Display and Visualisation These three chapters forming Part III - Display and Visualisation of Dynamic and Mobile GIS Investigating Changes in Space and Time examine the challenges of visualisation within the constraints of mobile GIS particularly the small-screen of a typical PDA but also the limitations of using only GPS as a positioning system. It is noted that in all three chapters it is the visualisation of transportation networks that is under consideration. In Chapter 8 Malisa Plesa and William Cartwright remind us that the 240 x 320 pixel resolution and 16-bit colour display of the typical PDA restrict the appearance of a displayed map. So although inexperienced users express a preference for realistic visualisation photorealism for example is very difficult to achieve within the PDA environment. A series of tests including a navigation task were given to ten subjects. These tests required representing a downtown area realistically using oblique photography and non-realistically and determining their usability. The tests showed that the non-realistic map was more effective. For example the slight tonal variations required to display photography could not be shown on the PDA limiting its utility for the display of realistic imagery. The non-realistic map was able to utilise a series of colours that achieved the maximum contrast and legibility available from this form of map delivery. As well as the results obtained showing that non-photorealistic graphics are more effective than photorealistic graphics in the context of 3D mobile cartography non-realistic representations are easier to develop than realistic scenes so are more suited to delivery on mobile devices. Plesa and Cartwright s test although involving transport networks was for pedestrians the representation of buildings and other neighbourhood features was as important as that for the road network. The extra rapid decision making required for vehicle navigation compared to pedestrians will