(contd. )

Example: Marine seismic maps can result in data which is periodically sampled in an unusual fashion.

Figure(3.2.11)

In figure above a boat towing a line of sensors moves with a speed of B knots in a direction perpendicular to an ocean current of speed C knots. The sensors are uniformly spaced temporal sampling period by T. How is the underlying spatial processing sampled?

Answer: To a first approximation, the sensors remain in a straight line, but that line is directed away from the direction of the boat movement at an angle given by

or,

Figure (3.2.12)

The resulting sampling grid corresponds to a sampling matrix: