A Topographic map is a site map that illustrates both natural and artificial features of a project site. For smaller sites, the information may be gathered by traditional survey methods using a robotic total station, real-time kinematic GPS and terrestrial laser scanning. For large sites, it may be more appropriate and cost-effective to use aerial mapping technology or LIDAR technology. The collected information is transformed to produce a digital surface model, a 3-D representation of a terrain’s surface, including all objects on it. The terrain’s surface is depicted through the usage of contour lines, grade lines, and spot elevations. Topographic contours can be shown at any interval that is specified by the client. In areas of steep terrain a larger contour interval can show the topography without crowding the map that would be introduced by a smaller contour interval. In areas of relatively flat terrain, a smaller contour interval is necessary to show the detailed changes in topography in a meaningful way. Generally these types of surveys are provided to engineers, architects, geologist, and building contractors for design and build purposes.