 Secondly, though he follows Bufalini in using a figure-ground representation of built space with blocks and building shaded in a dark poché, Nolli represents enclosed public spaces such as the colonnades in St. Peter's Square and the Pantheon as open civic spaces.Finally, the map was a significant improvement in accuracy, even noting the asymmetry of the Spanish Steps.The map was used in government planning for the city of Rome until the 1970s; it was used as a base map for all Roman mapping and planning up to that date.