<p>Ptolemaic is a computer application for music visualization and analysis written in the Java programming language. The software is designed to aid in the analysis of all types of Western music using established analytical techniques, including tonal functional analysis (Harrison 1994), pitch-class set analysis (Forte 1973), hierarchical linear analysis (Schenker 1935, Jones 2002), tonal pitch-space analysis on the Tonnetz (Riemann 1915), pitch-class set analysis (Forte 1973), and transformation analysis (Lewin 1987). Musical works and excerpts may be opened and saved using the de-facto standard music notation interchange format, MusicXML. To assist in analysis, Ptolemaic can display the music on a pitch/time graph, on a pitch-class/time graph, on a step-class/time graph (also called a diatonic lattice) (Jones 2002), on the Tonnetz, or using filtered point-symmetry (Douthett 2008). Pitch classes and chords are color coded so that the user can easily correlate them across each graph. The benefit of having a software tool to visualize and perform certain analysis tasks is in automating processes that are normally time-consuming for the musician, thus allowing the music scholar to focus on the musical issues, rather than the technical issues of graphing, and calculating chord classes. Ptolemaic provides useful ways of visualizing a piece of music and tools for gaining more information about that music, so that the user can efficiently make informed musical decisions about the music and preserve that analysis for future study.</p>