A method determines a partial area of a map which is described by features, the partial area describing the remaining range of a motor vehicle. An energy-storage system supplies a drive system which acts on at least one wheel of the motor vehicle. The remaining range is determined as a function of energy stored in the energy-storage system using an algorithm which expands from a current position of the motor vehicle. The method uses divides the map into geometric, in particular rectangular, structures of equal size. Whenever, in the context of the expansion, a feature lying in a structure or corresponding to a structure is added, the structure is added to the partial area.