1. A method for enhancing multiple feature lithography, the method comprising: generating a plurality of maps each associated with a particular one of a plurality of circuit features, each map mapping an illumination field comprising a plurality of point sources and indicating, in terms of a process metric and for each point source, a level of feature quality that will result from using the each point source to image the each circuit feature; adjusting one or more characteristics of a mask representing the plurality of features to improve the feature quality; and identifying, based on the maps, a group of one or more of the point sources that, if used to image the circuit features onto a target surface, will result in an overall feature quality level equal to or greater than a predetermined quality threshold, the group identified by: calculating a contribution value for each point source, the contribution value indicating an overall impact of the each point source on the feature quality of the circuit features; ranking the point sources based on the respective contribution values; and excluding at least one point source that does not meet a predetermined rank threshold.