Obtain data values for a vector plotted on top of a colorplot

I have plotted a colour plot of current speed, with depth on the y axis and time on the x axis.

I have a line which tracks tidal elevation, with varying depths across time within the water column.

My question is: how do I recieve current speed values for each time step along my line.

Figure shown below is what I have produced so far, I'm attempting to measure the difference in current speed experienced by both the soid and dotted black lines.

[Charlie Milford]

Any suggestions? I think it should be relatively simple I just cant think how it would be done

Answer 1

[Moksh]

Hi Charlie,

As per my understanding you have plotted the above graph in your code. So you might already have the current speed values on the y-axis and a constant speed value represented by the dotted line. So for the following part of your query you can simply create a difference vector of the same dimensions as y and use the 'abs' function of MATLAB to calculate their absolute difference.

You can you the following example code for this

% Your plotted speed values (I am using 100 random values)
y = rand(1, 100);

% Dotted line value (Constant speed value represeneted by the dotted line)
y_dot = 0.4;

% Number of speed values (Dimensions of the y-vector)
sz = size(y);
diff = zeros(sz);

for i = 1 : sz(2)
    diff(i) = abs(y(i) - y_dot);
end

You can use the following documentation for further understanding of for-loops and 'abs' function in MATLAB.

https://in.mathworks.com/help/matlab/ref/for.html

https://in.mathworks.com/help/matlab/ref/abs.html

Hope this helps!