A DEM Optimization Algorithm for Enhancing Efficiency in Highway Design

To address the engineering challenges of Digital Elevation Model (DEM) data storage redundancy, low elevation query efficiency, and discontinuous elevation between adjacent grids in highway design, this paper proposes a DEM hierarchical tile caching and high-efficiency query optimization algorithm adapted to linear engineering projects. The algorithm adopts a group-block two-level structure for grid division, integrates DEFLATE lossless compression and Least Recently Used (LRU) cache scheduling, and embeds bilinear smoothing interpolation. Test results show that the algorithm achieves a compression ratio of 20:1, completes the query of one million elevation points in less than 1 second, and delivers a more than 30-fold performance improvement over traditional methods, which can fully satisfy the real-time performance and accuracy requirements of highway design.