Design of Webgis for Computer-Aided Design Data Transformation and Road Topography Visualization Based on Digital Elevation Model

Abstract

Road engineering drawings are commonly archived as two-dimensional CAD files whose layers, entities, curves, and local topology do not directly form analysis-ready geospatial objects. This paper presents and evaluates a WebGIS artifact that transforms CAD road drawings into traceable 2D GeoJSON, reconstructs roads, buildings, and bridges, samples elevation from Indonesia's National Digital Elevation Model (DEMNAS), and automatically produces 3D terrain-following models. Semantic layer roles are assigned using a verified reference table. When ambiguities arise, the system detects layer roles based on normalized names, entity types, geometric characteristics, and spatial relationships, exposing the inferred roles for user review. The evaluation was conducted using 30 heterogeneous CAD files in DXF format. All files were processed, all 20 system-level functional scenarios passed, and DEMNAS covered all 39,779 requested station points. The weighted effective vertex-retention rate was 99.87 percent, and 23,659 of 23,661 output features were geometrically valid. Internal elevation-chain consistency produced a weighted MAE of 0.380 m and RMSE of 0.577 m.