At large scales ( urn:x-wiley:grl:media:grl58789:grl58789-math-000110 km, urn:x-wiley:grl:media:grl58789:grl58789-math-00021 Ma) drainage networks appear to have a synchronized response to uplift and erosional processes. At smaller scales erosion generates complex landforms. Here, cross wavelet spectral transformation of longitudinal river profiles is performed to develop a framework that unifies these scale‐dependent views of landscape evolution. Distance‐elevation and time‐elevation profiles are transformed using a continuous wavelet approach to determine where signal power resides and appropriate scaling regimes. Cross wavelet spectral power is then calculated to determine scales of similarity and disparity between river channels. Spectral power of rivers draining Angola are compared to lithology, biota, precipitation, and gravity data to examine origins of river shapes and commonalities. Most power and commonalities reside at long wavelengths and timescales (>100 km, >1 Ma). The presence of commonalities between drainage networks is expected for systems in which large signals (e.g., uplift) are forced through random media (e.g., lithology, biota).