The SuperDARN Assimilative Mapping (SAM) procedure uses the "optimal interpolation" method of data assimilation to obtain complete maps of electrostatic potential by optimally combining SuperDARN observations and a statistical convection model. This method weights the contributions of the observations and the statistical model based on the respective error properties of each source of information. For time periods with few observations available, the solution will be largely determined by the statistical model. The statistical model used is the CS10 model [Cousins and Shepherd (2010), A dynamical model of high-latitude convection derived from SuperDARN plasma drift measurements, J. Geophys. Res., 115]. The SAM procedure is described in more detail by Cousins et al. (2013), SuperDARN assimilative mapping, J. Geophys. Res., 118.