An Algorithm for Converting Contours to Elevation Grids

Some of the test questions for the National Council of Architectural Registration Boards deal with the site, including drainage, regrading, and the like. Some questions are most easily scored by examining contours, but others, such as water flow questions, are best scored from a grid in which each element is assigned its average elevation. This document describes a method for creating an elevation grid from a set of contour lines. The general objective is to calculate the perpendicular distances from the center of a grid element to two nearby contours of differing elevation and to assign an elevation to the grid element based on the relative distances from each contour. An appendix displays such a determination. (Contains 12 figures.) (SLD)