Grainmap splits an audio file at onsets and displays each slice as a region on a map. Regions which are nearby on the map correspond to audio slices that are nearby in time. Brightly colored regions correspond to loud audio slices. Darker regions that have a few bright patches correspond to low-volume audio slices that have a few loud peaks. Colors are chosen so that each region is visually distinguishable from its neighbors.
Once the audio file is loaded, clicking on any particular region causes the corresponding audio slice to play. Slices are played continuously forward and backward. Dragging your mouse across the map creates a granular style effect.