3D spatial modeling of Canada's critical infrastructure using mobile lidar technology

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Accurate and up-to-date 3D spatial models of critical infrastructure (e.g. physical facilities) across the ten sectors ranging from health, communication, energy and utility, etc. to transportation) are critical to the health, safety, security and economic well-being of Canadians and the effective functioning of governments in Canada. The advent of airborne and terrestrial laser scanning (or lidar) methods has proven to be a powerful tool for creating and updating 3D city models. However, both methods have their limitations for rapid and cost-effective capturing of 3D point clouds from larger street sections. This is especially true if these sections include tunnels or if dense point coverage of the building facades is required. As a preferable option, mobile lidar - a vehicle-mounted laser scanning system operating at speeds of up to 100 km/h, should be used. Whilst on the move, it can scan infrastructure and the surrounding environment as a very high density 3D point cloud. The geocoding of points is made possible by interfacing the laser scanners with an integrated suite of positioning devices (GPS, inertial measuring unit, and odometer). However, emergency managers and other end-users have neither the tools nor the interest in processing point clouds - they want spatial objects (e.g. buildings) rather than point clouds. Due to huge data volumes and complexity of urban street scenes, converting 3D point clouds to 3D spatial models to date is operator-driven and requires a workflow comprising several processing steps. Existing methods stress the steps individually and there is no single software system that does all of the necessary steps from input to model creation. This research tackles the very challenging problem of 3D building reconstruction from point clouds by developing a comprehensive strategy and an innovative software system. Through integrating point clouds acquired from mobile lidar with those from airborne lidar and (static) terrestrial lidar, optical images, floor plans and 3D GIS data, both the outside and inside of buildings can be modeled in 3D, which can effectively support emergency evacuation and rescue route planning.