地理信息软件，可对图形进行矢量的打开，矢量图层等-Geographic information software, open vector graphics, vector layer

信号处理中的振幅谱和相位谱以及谱密度估计等-1) Calculation of: - One-sided amplitude spectrum - One-sided phase spectrum - Vector of frequencies. 2) The function can plot: - One-sided amplitude spectrum - One-sided phase spectrum. Two examples are g