Color Proportional to Height in Scatter3()

I am plotting data points in scatter3. The x and y coordinates are the location of a mirror, and the z value is the signal strength at that point. It ranges from 0 to 384.

I am trying to create a color array the same length as the data to be graphed in order to have different colors for the different heights. Right now I have this:

color=cell(384,1);
for j=1:384

    if (signal{j} <40)
        color(j)='r';
    elseif (signal{j} >= 40) && (sigal{j} <100)
        color(j)='g';
    elseif signal{j} >=100
        color(j)='b';
    end
end

Basically I am trying to check the height of the point and based on the height, put a color code into a 384x1 array. However I keep getting this error code:

Cell contents reference from a non-cell array object. (It also points to this part:

    if (signal{j} <40)

I am not sure why. The signal is a 384x1 double array.

Any help would be wonderful!

Answer 1

[Walter Roberson]

pointsize = 8;
[counts, ccode] = histc(signal,[-inf, 40, 100, inf]) 
scatter3(x,y,signal,pointsize,ccode(:));
colormap([1 0 0;0 1 0; 0 0 1]);

[Daniel]

That was amazing. Thanks so much!

Answer 2

[Daniel]

Ok...I got this to work...messed with the formatting and stuff,

but now it doesnt like a colormap of the data. It says

Array must be numeric or logical.

My formatting for scatter3 is

scatter3(x,y,z,colormatrix)

where colormatrix is a 385x1 matrix with entries of 'r','g','b'

sorta like {'r','g'.....}

Any ideas?