Our recent experience evaluating the development and implementation of a powerful new digital resource from the Boston Public Library's Norman B. Leventhal Map Center brings to mind the need to balance the exciting potential of visionary resources with present day limits on teacher and student technology access. We encounter this issue in many of projects we evaluate and in the school districts as well as informal educational organizations where we work. The evaluation process can provide a way for striking a balance between visionary expectations and the realities of the here and now.