用java实现的画板程序，支持直线，矩形，圆，椭圆等图元。另外，它还会把每步操作写进文件，进行回放。-Java the Sketchpad procedures implemented to support primitives such as lines, rectangles, circles, oval. In addition, it will each step included in the file for playback.

JAVA实现对遥感数据HDF4格式的文件进行读写操作-JAVA read/write HDF4 file