Abstract: As a mega mountainous city in Southwest China,Chongqing features densely clustered high-rises and concentrated populations in its urban areas.Under the perspective of intelligent transformation in new surveying and mapping,this study addresses safety challenges posed by complex spatial environments to low-altitude economic development.This paper focus on key technologies for obstacle extraction and analysis during the compilation of 2D and 3D low-altitude visual navigation charts.For geographical environments characterized by complex terrain and densely distributed high-rises,a technical framework for obstacle extraction in visual navigation charts is developed based on 3D real-scene modeling.The achievements are applied and demonstrated in Chongqing's citywide visual aeronautical charts compilation project,supporting follow-up processes including visual flight navigation and safety early-warning systems,thereby enhancing low-altitude flight safety operations.

Key words: real-scene 3D, visual aeronautical charts, mountainous city, low-altitude obstruction