In October 1985, a shallow-water localization experiment was performed 19 miles south of Panama City, FL [J. Acoust. Soc. Am. 88, 423--433 (1990)]. The experiment involved a 450-Hz source placed 2.2 km from a vertical array of hydrophones in 33 m of water. Passive localization of the source using MVDR processing was successful after extensive ``fine tuning'' of the environmental parameters. In recent years the high-resolution sector-focusing (SF) processor has been developed for robust estimation in a mismatched environment, and has shown promising results when applied to simulated data. This work reports the application of the SF method to the Panama City data. Used for localization, greater tolerance to mismatch is evident. Furthermore, sector focusing may be applied as a parameter subspace technique for attaining high-resolution inversion of environmental parameters.