Modified Transcript: If we think of this piece of paper as the bedrock beneath the ice, then we could call the white areas on this piece of paper places of strong reflectivity. The black areas, then, would be places of weak reflectivity. We are using this information to create a map of the reflectivity of the bedrock. You could compare our task with that of a person who creates topography maps of the surface of the earth using height measurements. We are doing a similar task, but we are creating a reflectivity map of the bedrock beneath the ice using radar.