IDL编写，对环境卫星进行辐射定标并计算NDVI值。程序设计，1、影像分块，在处理大数据时特别有用；2、XML读取，IDL提供了方便的读写XML的方法；3、日期转儒略日算法；4、表观反射率计算方法；5、字符串处理技巧等。

-IDL to prepare for environmental satellite radiometric calibration and calculate NDVI values. Program design, an image block is particularly useful when dealing with large data　2, XML reading, IDL provides a convenient way to read and write XML　3, the date of transfer Julian Day algorithms　4, the apparent reflectance calculation method　5, string handling skills.