Changes between Version 198 and Version 199 of UvmatHelp
 Timestamp:
 Feb 17, 2016, 11:43:35 AM (7 years ago)
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UvmatHelp
v198 v199 316 316  317 317 == 5  Field structures == 318 === 5.1 Griding of data === 318 === 5.1 Griding of data === #tps 319 319 Physical fields can be defined either on regular grids, either scattered on an unstructured set of positions. Some measurements techniques, like PIV or particle tracking, provided unstructured data, while most methods of analysis require data on a regular grid. This can be done by interpolation, defining a projection on a plane (with '''[!ProjMode]''' ='interp...', see [#ProjObject next section]). The three possibilities of griding are defined as follows: 320 320 … … 331 331 Fields may be alternatively obtained on a unstructured (gridless) set of positions. The coordinates are then described by coordinate arrays X(nb_points), Y(nb_points), Z(nb_points). The corresponding field values are then represented as variables U(nb_point),V(nb_point) for each vector component, or alternatively by V(nb_points, j, i), where i, j possibly stand for vector or tensor components. 332 332 333  '''Thin plate shell (tps) interpolation:''' #tps333  '''Thin plate shell (tps) interpolation:''' 334 334 335 335 This is a multidimensional generalisation of the spline interpolation/smoothing, an optimum way to interpolate data with minimal curvature of the interpolating function. The result at an interpolation position vector ${\bf r}$ is expressed in the form, (see ThinPlateShell).