最近几年来，地理信息系统无论是在理论上还是应用上都处在一个飞速发展的阶段。 GIS被应用于多个领域的建模和决策支持，如城市管理、区划、环境整治等等，地理信息成为信息时代重要的组成部分之一； “数字地球”概念的提出，更进一步推动了作为其技术支撑的GIS的发展。 与此同时，一些学者致力于相关的理论研究，如空间感知、空间数据误差、空间关系的形式化等等。 这恰好说明了地理信息系统作为应用技术和学科的两个方面，并且这两个方面构成了相互促进的发展过程。
XML Schema Summary ¶
This tutorial has shown you how to describe the structure of an XML document.
You have learned how to use XML Schema to define legal elements of an XML document, just like DTD. We believe that XML Schema, as a replacement for DTD, will soon be used in most Web applications.
You have also learned that XML Schema is perfect. Unlike DTD, XML Schema supports data types (data type) and namespaces (namespace).
Please refer to our XML Schema 参考手册 For more information about XML Schema
Now that you have learned XML Schema, what will you learn next? ¶
The next step is to learn WSDL.
WSDL is a schema-based language that describes Web service and how to access them.
WSDL can describe Web service, along with the message format and protocol details for Web service.
If you want to learn more about WSDL, please visit our WSDL 教程 .