The Research On Fast Display Of Electronic Chart System

Taking an Electronic Chart Display and Information System (ECDIS) as the background, and based on studying the data format and display principles of ECDIS, this thesis proposes a fast electronic chart display method in multi-charts mode. And it has been applied as a basis to design an ECDIS on embedded and real-time operating system VxWorks.At first, this paper describes the data format of ECDIS, and studies ShapeFile format in detail. On deep understanding of the two formats, it analyses the transformation between them and makes preparation for splicing of charts.In succession, there is a discussion about the technique of development on embedded system. It introduces crossing development mode on embedded system, embedded developing system Tornado, GUI frame Zinc of VxWorks, middle graphics layer UGL and multimedia library WindML. And furthermore, this paper studies graphics development on VxWorks deeply.Finally, this paper puts forward the fast splicing display principle and method of ECDIS. Based on the characteristics of data and display process, this paper proposed that reading chart files in the hard disk and drawing map are primary things which affact the speed of ECDIS display. We use memory buffer to reduce reading operation on hard disk and memory bitmap to reduce the region to draw. Also we take the method of copying between memory bitmaps to get the effect of map smooth moving.An ECDIS using this idea has been applied in ships navigation. And proved by practice, this application has resolved the fast display, splicing without boundary, changing maps automatically, infinite zoom and quick moving of maps, thus advances the performance of the system as a whole.