RGB map into numerical data

he image below uses an RGB scale (the values of the scale are displayed on the image) to show the magnetic field strength at each point on the map. I've been struggling to find a way to convert this image into an array that shows the x and y coordinates of the pixel along with the magnetic field value at each coordinate

Answer 1

[KSSV]

I = imread('IMG_2830.jpeg') ;

I1 = imcrop(I) ; % Exactly crop the required borders/ exclude axis
[nx,ny] = size(I1) ; 

x = linspace(0,360,ny) ; 
y = linspace(0,90,nx) ; 
[X,Y] = meshgrid(x,y) ; 

image([0 360],[0 90],I1);