Cartographer Andy Woodruff has developed an interactive map that capitalizes on the fact that Ohio has 88 counties- the same number of keys on a piano. The basic premise behind Woodruff's map is this: each of the musical notes associated with the 88 piano keys are assigned to a single county in Ohio. The result is a "musical map" that is very interesting and fun to experiment with. Notes can be assigned to counties based on a selected attribute. For instance, if the attribute chosen is square miles, the county with the lowest square mileage will be assigned the lowest frequency note that can be played on a piano and the county with the highest square mileage will be assigned the highest frequency note.
Once the notes are assigned according to an attribute, the map allows you to play a song, play the data, play a metro area, or play a route. Playing a song (the options are The Entertainer or Beethoven's Fifth) allows you to "see the geography of music" as the different counties are darkened to represent the different notes in the song. Playing the data tracks the 'scale' of the selected attribute (from lowest note to highest note), as the counties once again are darkened as their associated notes are played. Playing a metro area just allows you to hear the musical chord based on a metropolitan area based on the selected attribute. Finally, playing a route is a very interesting application of this map. You can enter a start county and a destination county, and a route is formed through Google Maps (the 'avoid highways' option is selected to allow for more interesting routes). The sequence of counties in this route is then played.
There is definitely room for this map to evolve into a much more powerful application. Currently, you don't have the ability to compose your own geographic music by either importing songs or sequencing counties into songs. You also can not interface with the virtual piano, so you are limited to moving the mouse of the map to compose sounds. Also, the numerical data is not displayed anywhere, so you can really only interpret the ordinal attributes of the counties (the overall order and their values with relation to one another).
Overall, this map is a very interesting application of the sonification of data. Woodruff points out that metal detectors and Geiger counters are practical examples of representing spatial data using sound. Although Woodruff's map is more artistic in nature, it is possible that his work could lead to some more interesting revelations in understanding the music of data, especially in the case of those who are visually impaired.