Contour plot slicing utility with non-linear adaptive contour spacing. Calls plot_2d.m and allows slice extraction. 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 2D spectra is [0.02 0.2 0.02 0.2]. The first pair of num- bers refers to the positive contours and the second pair to the negative ones.
* 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;
* ncol is a number of colors in the colormap (around 256 is fine);
* m is the curvature of the colormap: m=1 corresponds to a linear color ramp into the red for positive contours and into the blue for negative contours. A reasonable value for high-contrast plotting is 6.
* 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 one or two sweep widths, Hz
parameters.spins cell array with one ot two character strings specifying the working spins.
parameters.offset one or two transmitter offsets, Hz
parameters.axis_units axis units ('ppm','Hz','Gauss')