The theory of Tonal Pitch Space (TPS) enables us to quantify the distance between chords. In this paper, we present a harmony analysis based on TPS in which the metrical distance of chords reflects the difference of keys and functions. Given a sequence of Berklee chord names, our analysis system assigns possible keys with degree names for each chord and the sequence results in a complicated network of chord progression. Then, the system selects the shortest path in terms of chord distance, that is regarded the most plausible interpretation.