The Polarimeter to UNify the Corona and Heliosphere (PUNCH) mission will remotely observe solar wind transients with high signal-to-noise ratio, high-cadence, high-resolution polarized white-light images. Using different polarization states, an important PUNCH data product will be polarization ratio images. In the small-Sun limit, and using a simple line-of-sight density distribution that resembles a corotating interaction region (CIR), we analytically investigate how the polarization ratio will provide three-dimensional location information and what the uncertainty in this estimated location is.