Figure 1
From: A tutorial in displaying mass spectrometry-based proteomic data using heat maps
Distance Measures. A simulated example of distance measurements using 4 measurements on 8 samples. On the original scale, measurements in A and C are closest in location, while A and B are the most correlated. On the standardized scale, correlation distance does not change, but measurements A and B now are very similar in location. Note that D has a large negative correlation with the A and B, so its correlation distance (using Equation 2) is low.