In this section, we discuss the theory of estimating the prediction filter for
plane wave. We use one and two plane waves as examples. First, we prove that
plane wave is predictable. Then we show how to estimate the spatial prediction
filter for both frequency-independent grids (**FIG**) and frequency-dependent
grids (**FDG**).
The difference is also the advantage of **FDG** over **FIG**. In the
appendix, we extend our theory to N plane waves.

- Wavefield composed of one plane wave
- Wavefield composed of two plane waves
- Estimating the spatial prediction filter

11/11/1997