qt 中的一个绘图例子，附有代码和运行后的图片，是一个正弦曲线-qt a drawing in the example code and run with the picture, is a sine curve

在grads绘图时运行代码给1000hPa、925hPa、850hPa。。。等气压层上的地形给予阴影处理。-Drawing the grads to run the code to 1000hPa, 925hPa, 850hPa. . . Pressure level terrain on the other to give shading.