电气图是一种描述电气系统或装置的结构、原理、功能等的工程语言,在电气系统设计中具有十分重要的地位.为此,给出了一种基于 XML(Extensible Markup L anguage)元语言实现的矢量电气图标记语言 Xvg ML(Ex-tensible Vector Graphics Markup L anguage),介绍了其设计、实现与优化过程.Xvg ML 兼具表达几何特征和电气物理量，因而有效地克服了一些矢量图形语言对电气系统描述能力的不足.Xvg ML 继承了 XML 的规范、简单、可扩展等特点,是一种对象化描述的信息语言,适合于与知识系统集成的应用.Xvg ML 在基于 Web的智能设计系统、产品报价系统和异构系统数据交换等方面有着较好的应用前景

Electrical drawing is an important engineering language to describe the structure, principle, function and etc. of electrical system and equipment. This paper proposes an XML based language, XvgML, which is designed to represent the electrical drawings. The XvgML definition includes three steps: establishing the object model, defining and naming the elements and properties, and compiling the DTD document. Two kinds of method can be applied to optimize XvgML. One is to remove the property equal to the default value which is set in DTD document, the other uses LZW algorithm to compress the XvgML document. These two methods make an obvious effect to reduce its storage and promote application performance. XvgML is composed of geometry elements and electrical elements so that it is able to model electrical systems and equipments. It is more powerful than other vector graphics languages with only geometry elements. With inherited from XML, XvgML is well formed, simple and extensible, and can be well integrated with knowledge based system. An example of electrical circuit layout Intelligent CAD has been build, it benefits from using XvgML as the intermediate language between the CAD engine and expert system. In short, XvgML will be widely used as an electrical graphic format in Web based Intelligent CAD system, Web based quoting system, or as an intersystem data exchanging medium.