Lets say I have a 4-D numpy array (ex:
np.rand((x,y,z,t))) of data with dimensions corresponding to X,Y,Z, and time.
For each X and Y point, and at each time step, I want to find the largest index in Z for which the data is larger than some threshold
So my end result should be an X-by-Y-by-t array. Instances where there are no values in the Z-column greater than the threshold should be represented by a 0.
I can loop through element-by-element and construct a new array as I go, however I am operating on a very large array and it takes too long.