Integrated Multi-Resolution DEM Generation: Merging Airborne LiDAR and CartoDEM forSeamless Terrain Modeling

Abstract. Accurate and continuous Digital Elevation Models (DEMs) are essential for hydrological modeling, terrain analysis, and large-scale geospatial planning. However, integrating elevation datasets from disparate sources—such as high-resolution airborne LiDAR and satellite-derived CartoDEM—requires careful handling of differences in spatial resolution and vertical accuracy. This study presents a structured workflow for generating integrated multi-resolution DEMs by merging airborne LiDAR data with CartoDEM products at 10 m and 30 m resolutions. The LiDAR point cloud was processed and resampled to a 30 m posting. Validated the quality of the derived DEMs with respect to 370 height control points, resulting in vertical RMSE of 1.5 m. For integration of different elevation datasets, a buffer-based blending approach was implemented using inverse distance weighting (IDW) interpolation across a 300 m transition zone, enabling smooth and gradual merging between the two datasets. This ensured the preservation of fine-scale terrain details from LiDAR while achieving seamless spatial continuity through CartoDEM support in peripheral regions. Quality checks were carried out using hillshade visualization and cross-sectional profile analysis across transition zones, ensuring no artefacts or elevation discontinuities persisted after merging. The final DEM maintains the fidelity of LiDAR-derived microtopography while leveraging CartoDEM for edge completeness and extended coverage. The workflow demonstrates a practical and scalable multi- resolution elevation model generation method, supporting broader geospatial initiatives and national mapping programs.