# Dictionary:tau-*p* mapping (τ-*p*)

An unstacked seismic record or a common-midpoint gather can be described in terms of slope d*t*/d*x* = *p* and intercept time τ, the arrival time obtained by projecting the slope back to *x* = 0, where *x* is source–geophone distance; see Figure T-1. The transform process is also called **slant stack**, the **Radon transform**, and **plane-wave decomposition**. Filtering can be done on the τ-*p* map and the filtered result transformed back into a record. Negative offsets can be padded with zeroes to avoid wraparound problems. See Diebold and Stoffa (1981)^{[1]}. Similar to **tau-gamma mapping**, where gamma is angle of emergence, gamma = γ = sin^{–1}(*pV*_{0}).

## References

- ↑ Diebold, John B.; Stoffa, Paul L. (1981). "The traveltime equation, tau‐pmapping, and inversion of common midpoint data".
*Geophysics***46**(3): 238–254. doi:10.1190/1.1441196.