Abstract: In this paper, we aim to address the challenge of quickly grasping the natural conditions along linear projects during the planning and demonstration stages. This difficulty arises due to the long routes, wide ranges, and complex natural environments involved. To overcome this, we utilize 3D real scene data as the above-ground spatial base, 3D geological model data as the underground spatial base, and thematic data as the data element base. Through this approach, we construct a 3D spatial scene that seamlessly integrates both above-ground and underground aspects.Subsequently,we have developed a process for conducting 3D site selection demonstration analysis in linear engineering based on this 3D scene.To illustrate the effectiveness of our approach, consider the proposed construction of expressways in Qingdao as a case study. This analysis can quickly understand the terrain and topography, actual situation, and geological fault structures along the line, significantly enhance the efficiency and quality of site selection for linear engineering projects. Overall, our work presents a novel model for conducting site selection demonstrations in three-dimensional spatial scenarios for linear engineering projects.

Key words: the ground-underground integration, linear engineering, site selection demonstration, 3D real scene, 3D geological model