Built-in colormaps:
The MATLAB has numerous built-in colormaps which are named; the reference page on colormap shows them. Calling the function colormap without passing any arguments will return the present colormap that by default is one known as the jet.
The following stores the present colormap in a variable map, gets the size of the matrix (that will be the number of rows in this matrix, or in another word the quantity of colors, by 3 columns), and shows the first five rows in this colormap. If the present colormap is the default jet, then this will be the outcome:
>> map = colormap;
>> [r c] = size(map)
r =
64
c =
3
>> map(1:5,:)
ans =
0 0 0.5625
0 0 0.6250
0 0 0.6875
0 0 0.7500
0 0 0.8125