Hello, I'm trying to get the correlation between 2 maps. I used the command: measure correlation #2 in_map #1 I also saved the resampled map. Then, I wrote a very simple python code that calculates the correlation coefficient as following: def compute_correlation(map1, map2): threshold = np.percentile(map1.flatten(), 99) # top 1% value mask = (map1 >= threshold) #& (map2 != 0) values1 = map1[mask] values2 = map2[mask] corr = np.corrcoef(values1, values2)[0, 1] return corr Although it is considered masking as it is done in ChimeraX, I was never able to get the correlation value I got from ChimeraX. I got 0.1 from the python code and 0.68 in ChimeraX. Any suggestions? Thank you -- Muhamed Amin, Ph.D Assistant Professor of Physics University of Groningen, Groningen, Netherlands