Computer graphic display of analyses

Two techniques are described for incremental plotter display of isopleths, starting from a regular array of function values. The first is a direct approach, in which a single isopleth is tracked through a grid from start to finish. The second, indirect technique, scans an entire grid array of function values, inversely interpolating all isopleth intersections with a fine mesh, and then arranges these intersections contiguously. In both methods maxima and minima points are determined by quadratic interpolation methods, also attempts are made to minimise actual plotter operating time. The indirect method is logically simpler from the programming aspect, and enables exact determination of isopleth locations. The direct method, however, does not require the use of secondary storage on a CDC 3600 computer, and consequently its execution time is shorter. Techniques for representation of fluid flow are described. A streamline method starting from basic flow component analyses is discussed. Each streamline is tracked through the grid in incremental steps, the size of which depends on an estimate of the streamline curvature. Singularities are explicitly determined by finding zeros in the field of total wind speed.