Volume isosurface plotting utility with non-linear adaptive isosurface spacing.The function is useful for NMR data where small cross-peaks must be adequately contoured next to large diagonal peaks. Syntax:
The following functions are used to compute contour levels:
* xmax and xmin are calculated from the spectrum;
* delta is the minimum and maximum elevation (as a fraction of total intensity) of the contours above the baseline. A reasonable value for most 3D spectra is [0.02 0.2];
* ncont is the number of contours, a reasonable value is 20.
* k controls the curvature of the contour spacing function: k=1 corresponds to linear spacing and k>1 bends the spacing curve to increase the sampling density near the baseline. A reasonable value is 2;
* signs can be set to 'positive', 'negative' or 'both' - this will cause the corresponding contours to be plotted.
The following subfields are required inthe parameters structure:
parameters.sweep three widths, Hz
parameters.spins cell array with three character strings specifying the working spins.
parameters.offset three transmitter offsets, Hz
parameters.axis_units axis units ('ppm','Hz','Gauss')