Similarity Matrix

http://www.biomedcentral.com/1471-2164/8/353/figure/F5?highres=y

A similarity matrix is a matrix in which measures the similarities between data points o the variables being observes. The matrix works off o a scale made of different shades of colors to show whether two points are more very similar, somewhat similar, or no significant similarity at al. In the provided similarity matrix, the darkest squares show which points are significantly similar, while the lighter shades or and white show little or no significant similarity, respectively.