Fourier and Spectral Analysis
The correlogram and periodogram are used in a variety of fields, including hydrology, agriculture, forestry, meteorology, ecology, and sociology.
Example
See, for example, Ripley (1981, Chapter 5), and Bras and Rodriguez-Iturbe (1985, Chapter 6). The correlogram assesses spatial patterns and spatial correlation, while the periodogram identifies periodicities in the data.