The AEGIST Guidebook is an information guide that helps build the National Roadway Base Map by constructing a consistent, enterprise-level deployment of a spatial data infrastructure at State departments of transportation. The AEGIST Guidebook shows how agencies at all levels of government can work together to develop a consistent means of collecting, maintaining, and publishing spatial data. At a detailed, technical scale, the AEGIST Guidebook addresses the specific needs for defined objects and their attributes, including the required accuracy, resolution, and precision. At a higher, organizational scale, the AEGIST Guidebook shows how to construct a more reliable and sustainable spatial data governance and management structure based on civil infrastructure management.