Abstract. The spatial resolution determines the number of data and amount of information in a remotely sensed image of a given scene. The 'optimal` spatial resolution may be defined as that which maximizes the information per pixel, and this maximum is realized when the semivariance at a lag of one pixel (the average squared difference between neighbouring pixels) is maximized. For mapping, a spatial resolution should be chosen that is much finer than the 'optimal` spatial resolution as defined above. Airborne MSS images in both red and near-infrared wavelengths for three different dates and two sites were investigated to determine a spatial resolution suitable for mapping spatial variation in agricultural fields in the U.K. The spatial resolution most appropriate for mapping the spatial variation in the images was between 0.5 m and 3 m.