A Geography Information System Base On Multi-touch Technology

Recently, multi-touch technology has been widely applied in a variety of touchrecognition systems, such as small mobile devices with resistive and capacitive touchscreen. However, the vast majority of GIS (Geography Information System)applications are still operated by mouse and keyboard other than work conjunction withmulti-touch technology. The project aims to improve the characteristics ofhuman-computer interaction, and develop a desktop GIS operated by fingers directly. Aresearch is proposed for the requirements. Firstly, the hardware platform of the systemis built, using multi-touch technology based on optics and computer vision. Secondly, aseries of video frames containing the contact object is read and the frames is processed,after which the outer contour of all touch points is extracted and the coordinate of eachcontour center is calculated, to finish tracing touch point trajectory and transfer touchpoint information by TUIO (Table-Top User Interfaces Objects) protocol. Finally, thetrajectory can be recognized into correct interaction gestures which operate the GISthrough MapX. The author completed the three parts of the project, and finished thethesis on the research of the project.The thesis is divided into three parts. In the first part, a touch point tracingalgorithm is introduced, including video stream capture, image processing algorithms,contact contour extraction, tracking contacts, data communication, etc. In the secondpart, the definitions of six kinds of multi-point touch interaction gestures, as well as astate transition model of the gestures is presented, then a gesture recognition methodbased on contact trajectory is given according to the number of the touch points andstate of the touch gesture. The third part gives the architecture and the build process ofthe multi-point GIS. Finally, A comparison between mouse clicks and finger touchoperation is conducted, and system experimental results are analyzed.The project gives a GIS based on multi-touch technology that users can directlymanipulate by fingers to finish typical GIS functions. Compared with traditional GIS,our GIS offers better characteristics of human-computer interaction and user experience.