飞机初步设计时，界限法确定总体参数Matlab程序-Aircraft preliminary design, the boundaries to determine the overall parameters Matlab program

国家基础地理信息系统1:400万数据(1:400 million data in the national fundamental geographic information system)，介绍我国地理资源的主要内容，包括国界、省界、河流、铁路等的划分和分布情况，分类很具体，数据也很完善-National fundamental geographic information system 1: 4,000,000 Data (1: 400 million data in the nation