Topographic querying is the process of extracting data from a sensor network for understanding the graphic delineation of features of interest in a terrain. Query processing techniques based on localized computation and aggregation cannot be used to resolve topographic queries efficiently as resolution of such queries involves global collaboration among the sensor nodes (e.g., region identification). We explore an alternate approach for resolving such queries, which is based on construction and maintenance of topographic maps. We focus on the class of sensor systems involving dense, uniform deployment of sensor nodes over a two dimensional terrain. Our analysis shows that by maintaining additional state (map) in the system, the query processing costs can be reduced significantly in comparison with the state-of-the-art. Our simulation results show that the map construction overheads are amortized over a small number of queries.