Colour data from a vlaue

I have a value that ranges from roughly -5 to 10. From this I would like it so that when the value is high it returns red (or white) and for low blue/black with other colours in the middle.

However, all the colormap tutorials/references I have seen are for plotting graphs. I need hexadecimal values of the RGB so that I can write a KML file with them

Any help would be appreciated.

Answer 1

[Titus Edelhofer]

Hi Toby,

yes, colormap is usually used in connection with graphics. But there is nothing wrong in using the values for your purpose:

% get the values of a colormap, e.g. jet
f = figure('visible', 'off');
cm = colormap('jet');
close(f);

% limits
cmin = -5;
cmax = 10;

% now interpolate e.g. at 7
val = 7;
if val<=cmin
  index = 1;
elseif val>=cmax;
  index = size(cm,1);
else
  index = round(1 + (val-cmin) * (size(cm,1)-2)/(cmax-cmin));
end

% grab corresponding row:
rgb = cm(index,:);

Titus