Reconstruction of Contour Lines During the Digitization of Contour Maps to Build a Digital Elevation Model

TL;DR

This paper presents a method to accurately reconnect broken contour lines in digitized maps using Euclidean distance, gradient direction, and spline interpolation, improving the quality of digital elevation models.

Contribution

It introduces a novel approach combining distance, gradient, and spline techniques to restore broken contour lines during map digitization.

Findings

Effective reconstruction of broken contour lines.

Enhanced accuracy of digital elevation models.

Reduced errors in contour map digitization.

Abstract

Contour map has contour lines that are significant in building a Digital Elevation Model (DEM). During the digitization and pre-processing of contour maps, the contour line intersects with each other or break apart resulting in broken contour segments. These broken segments impose a greater risk while building DEM leading to a faulty model. In this project, a simple yet efficient mechanism is used to match and reconnect the endpoints of the broken segments accurately and efficiently. The matching of the endpoints is done using the concept of minimum Euclidean distance and gradient direction while the Cubic Hermite spline interpolation technique is used to reconnect the endpoints by estimating the values using a mathematical function that minimizes overall surface curvature resulting in a smooth curve. The purpose of this work is to reconnect the broken contour lines generated during the digitization of the contour map, to help build the most appropriate digital elevation model for the corresponding contour map.