In a recent paper (Levin, 1983), I derived the common midpoint (CMP) time-distance relations for reflection from a plane of arbitrary orientation when the streamer carrying the hydrophones was feathered by currents. The streamer was assumed to be straight but deviated at a constant angle γ. This assumption corresponds well to what is observed during marine exploration. I considered two cases: first, the CMP points chosen to be what they would have been in the absence of feathering and second, the CMP points selected to lie along a line perpendicular to the profile direction. The second choice is the one normally made and the only one I'll consider in this short note.
In the paper, I assumed the CMP points were allowed to extend from the origin, which was the point of coincident source and detector, to whatever distance from the line corresponded to the maximum source-to-detector separation. While this is a possible choice, it is not the choice of many of those who must process marine 3-D data. Instead they demand that all CMP points fall within a bin centered on the profile line. I shall call this choice “binning.”