Colormap, how to get the color of the sea

This is an interesting question to me. I wanted to create a nice colormap with very smooth and gradual transition from white to sea blue. I tried to do it manually in colormap but it does not work out very well. Anybody who has explored this, or know some developed colormap?

Many thanks

Answer 1

[Image Analyst]

Try a program where you can easily get the RGB values of some color of blue that you like, like (r,g,b) = (rBlue, gBlue, bBlue). Then use linspace().

numColors = 256; % Good value for 24/32 bit displays.
oceanRed = 15;
oceanGreen = 127;
oceanBlue = 230;
myColorMap = [linspace(oceanRed, 255, numColors)'/255,...
  linspace(oceanGreen, 255, numColors)'/255,...
  linspace(oceanBlue, 255, numColors)'/255]
imshow('cameraman.tif');
colormap(gca, myColorMap);
colorbar

[noor]

what does the function numColors do?

[DGM]

The variable numColors specifies the number of tuples (rows) in the colormap. It's easy enough to test.

numColors = 5; % change the value and see what happens

oceanRed = 15;
oceanGreen = 127;
oceanBlue = 230;

myColorMap = [linspace(oceanRed, 255, numColors)'/255,...
    linspace(oceanGreen, 255, numColors)'/255,...
    linspace(oceanBlue, 255, numColors)'/255]

myColorMap = 5×3

0.0588 0.4980 0.9020 0.2941 0.6235 0.9265 0.5294 0.7490 0.9510 0.7647 0.8745 0.9755 1.0000 1.0000 1.0000