How can I plot values from an XYZ image onto a CIE color space diagram?

here is the image I wouuld like to map it on: https://upload.wikimedia.org/wikipedia/commons/3/3b/CIE1931xy_blank.svg So far, I have generated coordinates from an xyz image as shown below (I'm not sure)

X = xyzImg(:, :, 1);
Y = xyzImg(:, :, 2);
Z = xyzImg(:, :, 3);

xCord = X / (X + Y + Z)
yCord = Y / (X + Y + Z)

I would like to map it onto the diagram to get the approximate wavelength, and ultimately, chlorophyll content. Is my code correct in finding the coordinates? and If so, how should I find the wavelength and/or the chlorophyll content?