Feature Querying the Texas Historic Overlay prior to any major highway construction or reconstruction project allows TxDOT and its consultants to ensure the preservation of historical and cultural resources. tool for cultural resource planning. With the Texas Historic Overlay, we can quickly and consistently locate and avoid possible historic archaeological sites that otherwise might be missed in planning for highway projects." The resource proved particularly valuable to a project in San Antonio, Texas. As part of the redevelopment of downtown San Antonio, the city wanted to renovate the historic Main Plaza located about a mile from the Alamo [the site of the most famous battle of the Texas Revolution] into a pedestrian-friendly plaza for residents and the millions of tourists who visit annually. First established in 1731 by Spanish settlers as the Villa de San Fernando, the Main Plaza has always been the center of San Antonio's municipal government. Soldiers killed during the 1810–1820 War for Mexican Independence are buried at the church along with the remains of the defenders of the Alamo. The Main Plaza also links to the historic San Fernando Cathedral and the nearby San Antonio River. PBS&J used the THO geodatabase to identify and avoid sensitive archaeological and cultural resource sites during construction activities as mandated by the Antiquities Code of Texas. Historical consultants laud the new resource because of its value in projects like the renovation of San Antonio's Main Plaza. Abbott said, "They say it has saved them so much time because we've been able to gather these resources, which have heretofore been scattered all over the state and were not being www.esri.com used, and bring them into one place where they are readily accessible." THO data is available to TxDOT and approved consultants to manage the state's cultural resources and develop historic trends in land use, development, and vegetation. Although some maps are restricted as a result of agreements between TxDOT and the individual libraries and repositories that own the paper copies, the rest of the maps are available to the public through the Texas Natural Resource Information System Web site at www.tnris.org. About the Author Ty Summerville is the geospatial project manager for PBS&J. He has more than 11 years of experience in this area. He can be reached at tdsummerville@pbsj.com. For More Information Understanding Map Projections and Coordinate Systems and Georeferencing Rasters in ArcGIS, both Web courses, are available from www.esri.com/training. ArcUser Summer 2009 23 Ar ArcUser Summer 2009 3 rc e um er 200 umm 20 0 mm 0