Rama Map is short for "Ramachandran Map". The Rama Map tool in Foldit displays a graph of the two key backbone angles in the protein.
The horizontal x-axis of the Rama map is the angle phi, the angle between the peptide bond of the previous segment segment and the alpha carbon of the current segment. The vertical y-axis is psi, the angle between the alpha carbon of the current segment and the peptide bond of the next segment.
Both phi and psi range from -180° in the lower left corner of the Rama Map to +180° in the upper right corner. The center of the Rama Map 0° for both phi and psi.
The colored regions in the Rama Map use ABEGO coloring to indicate favorable combinations of phi and psi for different secondary structures. These regions are different for each amino acid. Selecting a segment displays the Rama Map specific to that segment's amino acid. With no segment selected, the Rama Map displays generalized favorable regions. The more intense the color, the more favorable the combination of angles.
The blue region of the Rama Map corresponds to the "B" in "ABEGO", and indicates a backbone shape that likely to be found in a sheet, also known as "beta sheet".
The red region Rama Map corresponds to the "A" in "ABEGO" (so much for mnemonics) and indicates a shape likely to be found in a helix, also known as "alpha helix".
In the original Foldit interface, the Rama Map is available on the Actions menu. In the selection interface, the Rama Map is available on the Main Menu, which can be displayed using the lowercase "p" keyboard shortcut.