Interferometric phase observations are ambiguous, modulo 2 pi, and algorithms that
follow specific paths are used to "unwrap" the data, resolving the ambiguity. The cover
shows the results of six different path algorithms plus a benchmark (horizontal axis)
applied to five different data sets (vertical axis). Blue represents beginning, red
represents end. for details see the paper by Osmanoglu et al., pp. 3205-3220.