.. _modules: *************** Modules *************** .. _overview: Overview ========= The programs in this package are as follows: **read**: read a 3-column space, comma or tab delimited text file **partition**: partition a Nx3 point cloud into M windows of nx3 points with specified spacing between centroids of adjacent windows and with specified overlap between windows. **detrend**: returns detrended amplitudes of a Nx3 point cloud **sgolay**: returns the Savitsky-Golay digital filter of a 2D signal **spatial**: calculate spatial statistics of a Nx3 point cloud **lengthscale**: calculates the integral lengthscale of a Nx3 point cloud **spectral**: calculate spectral statistics of a Nx3 point cloud **process**: allows control of inputs to all modules (full workflow) **write**: write program outputs to a comma delimited text file **test**: program testing suite **plot**: program utilities for creating 2d and 3d plots These are all command-line/modular programs which take a number of input (some required, some optional). Please see the individual files for a comprehensive list of input options .. _process: Main program: process ===================== Calculate spectral and spatial statistics of a Nx3 point cloud Syntax ---------- You call the function like this:: () = pysesa.process(infile, out, detrend, proctype, mxpts, res, nbin, lentype, minpts, taper, prc_overlap) Parameters ------------ infile : str ASCII file containing an Nx3 point cloud in 3 columns Other Parameters ----------------- out : float, *optional* [default = 0.5] output grid resolution detrend : int, *optional* [default = 4] type of detrending. 1 = remove mean 2 = remove Ordinary least squares plane 3 = remove Robust linear model plane 4 = remove Orthogonal Distance Regression plane 5 = remove Savitsky-Golay digital filter, order 1 proctype : int, *optional* [default = 1, no spectral smoothing] proctype type: 1 = spectral only, no spectral smoothing 2 = spectral only, spectrum smoothed with Gaussian 3 = spatial only 4 = spatial + spectrum, no spectral smoothing 5 = spatial + spectrum smoothed with Gaussian mxpts : float, *optional* [default = 1024] maximum number of points allowed in a window res : float, *optional* [default = 0.05] spatial grid resolution to create a grid nbin : int, *optional* [default = 20] number of bins for power spectral binning lentype : int, *optional* [default = 1, l<0.5] lengthscale type: 1 = l<0.5 2 = l<1/e 3 = l<0 minpts : float, *optional* [default = 16] minimum number of points allowed in a window taper : int, *optional* [default = Hanning] flag for taper type: 1 = Hanning (Hann) 2 = Hamming 3 = Blackman 4 = Bartlett prc_overlap : float, *optional" [default = 0] percentage overlap between windows Returns [proctype = 1 or proctype = 2] ---------------------------------------- data: list x = centroid in horizontal coordinate y = centroid in laterial coordinate slope = slope of regression line through log-log 1D power spectral density intercept = intercept of regression line through log-log 1D power spectral density r_value = correlation of regression through log-log 1D power spectral density p_value = probability that slope of regression through log-log 1D power spectral density is not zero std_err = standard error of regression through log-log 1D power spectral density d = fractal dimension l = integral lengthscale wmax = peak wavelength wmean = mean wavelength rms1 = RMS amplitude from power spectral density rms2 = RMS amplitude from bin averaged power spectral density Z = zero-crossings per unit length E = extreme per unit length sigma = RMS amplitude T0_1 = average spatial period (m_0/m_1) T0_2 = average spatial period (m_0/m_2)^0.5 sw1 = spectral width sw2 = spectral width (normalised radius of gyration) m0 = zeroth moment of spectrum m1 = first moment of spectrum m2 = second moment of spectrum m3 = third moment of spectrum m4 = fourth moment of spectrum Returns [proctype = 3] ------------------------ data: list x = centroid in horizontal coordinate y = centroid in laterial coordinate z_mean = centroid in amplitude z_max = max amplitude z_min = min amplitude z_range = range in amplitude sigma = standard deviation of amplitudes skewness = skewness of amplitudes kurtosis = skewness of amplitudes n = number of 3D coordinates Returns [proctype = 4 or proctype = 4] ----------------------------------------- data: list x = centroid in horizontal coordinate y = centroid in laterial coordinate z_mean = centroid in amplitude z_max = max amplitude z_min = min amplitude z_range = range in amplitude sigma = standard deviation of amplitudes skewness = skewness of amplitudes kurtosis = skewness of amplitudes n = number of 3D coordinates slope = slope of regression line through log-log 1D power spectral density intercept = intercept of regression line through log-log 1D power spectral density r_value = correlation of regression through log-log 1D power spectral density p_value = probability that slope of regression through log-log 1D power spectral density is not zero std_err = standard error of regression through log-log 1D power spectral density d = fractal dimension l = integral lengthscale wmax = peak wavelength wmean = mean wavelength rms1 = RMS amplitude from power spectral density rms2 = RMS amplitude from bin averaged power spectral density Z = zero-crossings per unit length E = extreme per unit length sigma = RMS amplitude T0_1 = average spatial period (m_0/m_1) T0_2 = average spatial period (m_0/m_2)^0.5 sw1 = spectral width sw2 = spectral width (normalised radius of gyration) m0 = zeroth moment of spectrum m1 = first moment of spectrum m2 = second moment of spectrum m3 = third moment of spectrum m4 = fourth moment of spectrum .. image:: _static/pysesa_colour.jpg