“Atlantic Floor” is a composition for piano where the melody was determined entirely by the shape of the floor of the Atlantic Ocean along the 33.0205 latitude which runs from South Carolina to Morocco.

The philosophical motivation behind this composition was to use nature in art—not as an inspiration filtered through the artist’s experience and biases, but used directly as much as possible. While a landscape may be photographed, framed, and hung on the wall, in this case the shape of the bed of the ocean was taken to dictate completely the form and melody of the music.

Click here to listen to this piece on youtube.

The topography data for the music—the depth of the ocean along this latitude—was obtained from the website of the National Oceanic and Atmospheric Administration. The data, with depth shown in meters, is shown below. You can imagine, if you will, that this chart is a cutaway of the Atlantic Ocean with South Carolina at the far left, Morocco at the far right, and the heavy solid horizontal line at zero representing sea level. The jagged line is the ocean floor—though note that the width of the chart is not at all on the same scale used to represent the sea depth.

atlantic-floor-topography-data

The 33.0205 latitude intersects the American coastline a bit north of Charleston, South Carolina, specifically at Cape Island near the town of McClellanville. The melodic “trip” begins there, proceeding directly along this latitude and ending on the Moroccan coast a little south of the town of Sidi El Abed. (The choice of this latitude was somewhat but not completely random, as a beginning that included a decent stretch of shallow water was an attribute I was looking for.)

Transforming the shape of the ocean floor into a melody required just a bit of mathematics. From sea level to 120 meters below the surface was mapped to the G an octave and a half above middle C. Every additional 240 meters of depth was taken to indicate a pitch a half step lower. The deeper portions of the ocean, therefore, correspond with lower pitches. The entire depth-to-pitch mapping covered two octaves and is shown below with the pair of numbers next to each letter note representing the depth range in meters corresponding to that pitch.

depth-table

The data series (beginning at the North American coast and ending at the African mainland) was divided into 355 intervals and the depths at those intervals were translated into the pitches that became the melody. Each interval was taken to be the length of one quarter note. The rhythm of repeated melody notes was left to the composer’s discretion (so, for example, three quarter notes of the same pitch could be realized as three quarters, two dotted quarters, or a half followed by a quarter).

Since the pitches changed at irregular intervals and as the distances between these changes were a critical feature of the topography, I didn’t alter the timing of these distances to fit a regular or constant meter. Instead, the song’s meter varies throughout in order to fit with the rhythm of the pitch changes. The meter is written as measures of 10/8, 8/8, 6/8, and 4/8, with these time signatures helping to organize the driving meter which largely consists of a varying sequence of eighth note triples and duples.

Finally, the song begins and ends with an arpeggiated figure in 10/8 that carries no melody but serves to bookend the rest of the song.

Click here for a PDF of the sheet music.

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