pyacs.sol.helmert module

calculates Helmert transformation

pyacs.sol.helmert.helmert_matrix(x, y, z, tran=True, rot=True, scale=True, equilibrate=True)[source]

Generates a Helmert transformation matrix for a single point Can also create translation/rotation/scale transformation matrix

  • x,y,z – point geocentric coordinates (m)

  • tran,rot,scale – boolean telling that translation/rotation/scale will be included

  • equilibrate – (default True) changes the unit of the matrix so that x are in km and scale in mas for better conditionning of the matrix

Returns H

the transformation matrix as 2D numpy matrix

pyacs.sol.helmert.observation_equation_helmert_local(xf, yf, zf, xr, yr, zr, tran=True, rot=True, scale=True)[source]

Generate the linear transformation equation system for coordinate of a sites in two reference system. The equation system is generated for E,N,U components

  • xf,yf,zf – geocentric coordinates in the initial reference (also called ‘free’ frame)

  • xr,yr,zr – geocentric coordinates in the final reference (the reference frame)

  • tran,rot,scale – boolean telling that translation/rotation/scale will be included

Return A,B

the design matrix and observation vector


VCV not accounted yet

pyacs.sol.helmert.estimate_helmert(H_Gpoint_ref, H_Gpoint_free, vcv_xyz=None, psd=None, tran=True, rot=True, scale=True, lexclude=[], method='Dikin_LS', threshold=5.0, verbose=True)[source]

Estimates Helmert or transformation parameters between two sets of coordinates Default is a 7-parameters transformation (translation, rotation & scale)

:param H_Gpoint_ref : dictionary of Geodetic Points (Gpoint instance) used as reference :param H_Gpoint_free: dictionary of Geodetic Points (Gpoint instance) used as free :param psd: psd object from sinex library for post-seismic deformation :param tran,rot,scale: boolean telling if the transformation will use translation/rotation/scale :param method: ‘LS’ (Least-Squares) or ‘Dikin_LS’ (a sequence of L1 and L2 norm) estimation :param threshold: threshold value for outlier rejection (default 5.) :param verbose: boolean

pyacs.sol.helmert.find_outliers_Helmert(R, threshold=5)[source]

Returns index outliers points