Page 40 - Basics of MATLAB and Beyond

The contour function plots the contours using the current colour map’s
colours (see next section). Adding the specifier ’k’ to the end of the
argument list draws the contours in black. The spanplot function is
nonstandard and is included in the companion software.
You should experiment with these plots. Try typing help for each of
these plot commands. Explore the various ways of shading a surface, try
using different colour maps (see next section) or viewing angles (help
view), or try modifying the surface and replotting. Remember that
rotate3d can be used to switch on a click-and-drag three-dimensional
view changer: click down on the plot and drag it to alter the viewing
angle; release the mouse to redraw the plot. (If rotate3d is already
switched on, typing rotate3d again will switch it off.)

7.2 Colour Maps

matlab uses a matrix called a colour map to apply colour to surfaces and
images. The idea is that different colours will be used to draw various
parts of the plot depending on the colour map. The colour map is a list
of triplets corresponding to the intensities of the red, green, and blue
video components, which add up to yield other colours. The intensities
must be between zero and one. Some example colours are shown in this
table.

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