Contours Grid

This layer shows the division boundaries for the three sections of contours. Sanborn derived this contour dataset from LiDAR data produced by Dewberry as part of a 2012 Virginia FEMA LiDAR project. The class-2 ground points were used to create a terrain surface with approximate point spacing of 2.5' (equal to the average spacing of the LiDAR class 2 ground points.) No thinning was done to the terrain surface. Using ArcGIS 3D Analyst tools, a 2' interval contour polyine feature class was derived from the terrain surface. Resulting contours were thin simplified, using ArcGIS tools, to remove extraneous vertices from the contours, and the contours were diced. This was done to increase efficiency in using the data for subsequesnt users.