Research On Vector Electronic Charts Services Based On HTML5

With the shipping needs and rapid development of Internet technology, Web electronic chart came into being. However, as users on the use of web electronic chart and demand for interactive experience have become higher and higher, traditional Web electronic chart technology has gradually difficult to meet the needs of users. On one hand, Web electronic chart that based on raster data has obvious defects in chart information analysis and interactive capabilities. On the other hand, a number of Web vector electronic chart display technology based on plug-ins also exists some problems that need to download and install, difficult to cross-platform and cross-browser and bring unsafe hidden dangers, etc. The emergence of HTML5provides a new method to solve the above problems that can construct vector, cross-platform and cross-browser’s Web electronic chart service.In this paper, against with problems that existing in traditional Web electronic chart service, combined with the Canvas, WebSocket and many other new features of HTML5, conducted in-depth research in vector electronic chart services and related applications that based on HTML5,completed the main work is as follows:(1) Web vector electronic chart data organizationCompared and analyzed a variety of chart data organization form, select Shapefile as Web vector chart services data transfer format. Studied the method of using JavaScript to read Shapefile format chart data, thus, access to a variety of points, lines and surfaces object’s geospatial information and attribute values which in chart data online.(2) Vector electronic chart rendering based on HTML5CanvasBased on Shapefile data, combined with drawing mechanism of HTML5Canvas and refer to S-52/CJ-52chart display specification, designed and implemented drawing and rendering of point symbols, line symbols, and are symbols that based on Canvas.(3) The ship real-time monitoring based on HTML5WebSocketDesigned and implemented of vector electronic chart service Http server as well as WebSocket server that conduct ship dynamic monitoring applications based on Node.js and PostgreSQL database. Implemented the server-side and Web client real-time and two-way communication that using WebSocket interface supported by HTML5, and realized dynamic and real-time rendering of ship on the basis of vector electronic chart display.This article conform to the development and trends of Web technology, put forward a kind of Web electronic chart service mode that is new and based on HTML5, broadens the research ideas of Web electronic chart service and has a certain theoretical significance and application value for realizing more functions and better user experience.