你不可能有的CAD读写程序，主要用于打开CAD产生的各种文件，如：dwg,dwf等，可以提取图章信息-You can not have program for reading CAD,but you can open all kinds of files made by CAD, such as dwg,dwf etc. you get the information of picture

<p><strong>GIS (Geographical Information System) is a computer support system that represents data using maps. It helps people access, display and analyse data that has geographic content and meaning. For those not familiar with GIS, it u