The standard practice of using moderate resolution satellite imagery for carbon flux studies at Ameriflux sites is called into question. In this study, a flux footprint model was implemented for modelling the carbon source areas for an Ameriflux site in Oklahoma using one year of carbon flux and meteorological measurements. A sensitivity analysis was conducted using cell sizes from 1 m to 30 m for the study site. The results indicate that over 95% of the source locations are within 93 m of the carbon flux receptor. Knowing the spatial accuracy is typically no better than ½ cell size, suggests that cell sizes of less than 45 m introduces far greater uncertainty than is appropriate.