7.7 Gridding Example

MATLAB provides a biharmonic spline interpolation since its very beginnings. This interpolation method was developed by Sandwell (1987). This specific gridding method produces smooth surfaces that are particularly suited for noisy data sets with irregular distribution of control points. As an example we use synthetic xyz data representing the vertical distance of an imaginary surface of a stratigraphic horizon from a reference surface. This lithologic unit was displaced by a normal fault. The foot wall of the fault shows more or less horizontal strata, whereas the hanging wall is characterized by the development of two large sedimentary basins. The xyz data are irregularly distributed and have to be interpolated onto a regular grid. Assume that the xyz data are stored as a three-column table in a file named normalfault.txt.

     4.32e+02   7.46e+01    0.00e+00     4.46e+02   7.21e+01    0.00e+00     4.51e+02   7.87e+01    0.00e+00     4.66e+02   8.71e+01    0.00e+00     4.65e+02   9.73e+01    0.00e+00     4.55e+02   1.14e+02    0.00e+00     4.29e+02   7.31e+01    5.00e+00     (cont'd)

The first and second column contains the coordinates x (between 420 and 470 of an arbitrary spatial coordinate system) and y (between...