Figure 2. Comparison of two 3-D recording swaths, A and B. Swath A honors the even-integer rule because it spans 10 receiver lines in the cross-line direction (east-west) and eight source-line spacings in the in-line direction (north-south). Swath B violates the even-integer rule twice because it spans 11 receiver lines in the cross-line direction (violation one) and seven source-line spacings in the in-line direction (violation two). The source-line and receiver-line spacings and the source-station and receiver-station intervals used in this 3-D design are 1,320 feet, 880 feet, 220 feet, and 110 feet, respectively.