1. An automated method for applying a visual classification scheme to display units of a map based on one or more known data values associated with a subset of the display units, the method comprising: identifying a target region within the map, the target region comprising a plurality of display units; obtaining interpolated data values for only a subset of the display units within the target region, the number of the display units in the subset being less than the total number of the display units in the target region, the remainder of the display units within the target region not having known data values and interpolated data values therefor; determining, by one or more processors, whether all of the display units within the target region can be assigned to a same one of a plurality of classes based on the interpolated data values obtained for only the subset of the display units within the target region; and in response to determining that all of the display units within the target region can be assigned to the same one of the plurality of classes based on the interpolated data values obtained for only the subset of the display units within the target region, assigning all of the display units within the target region to the same one of the plurality of classes and assigning a visual indicator to each display unit in the target region based on the class to which the display unit was assigned.