LiDAR Surveying for Urban Infrastructure: A Case Study of the Toronto Transit Commission

Project Overview: Metro Station LiDAR Surveying

In April 2021, DCMS undertook a comprehensive LiDAR surveying project involving three metro stations within the Toronto Transit Commission (TTC) system. This initiative aimed to obtain a highly detailed understanding of the structural and functional aspects of each station, including ticketing halls, entrances, platforms, stairwells, and significant structural elements. By leveraging LiDAR technology, DCMS was able to capture existing conditions with millimeter precision. This high level of accuracy was crucial in providing the TTC with the essential data needed for infrastructure assessments, upgrades, and long-term renovation planning.

The Importance of LiDAR Surveying in Urban Transit Systems

Urban transport systems often contend with unique challenges, such as irregular designs, tight timelines, and continuous user traffic. Traditional surveying methods frequently fall short in providing the necessary accuracy and efficiency. LiDAR surveying stands out as an innovative solution, offering numerous advantages:

• Speed and Efficiency: LiDAR can capture millions of data points in a matter of minutes, significantly reducing survey time compared to conventional methods.

• High Precision: The technology enables accurate reflections of complex geometries and existing environmental conditions, providing data that is critical for future planning and infrastructure additions.

• Minimal Disruption: Surveys can be conducted quickly and efficiently, minimizing the impact on daily operations and ensuring that transit services continue uninterrupted.

The combination of these advantages makes LiDAR surveying an ideal choice for projects like the TTC metro stations.

Challenges Faced and Innovative Solutions

Despite the advantages of LiDAR technology, DCMS encountered several challenges typical of urban environments during the TTC project, all of which were resolved through strategic planning and innovative solutions:

High-Traffic Environments

Conducting LiDAR surveys in the bustling environment of metro stations posed a challenge. With thousands of commuters passing through daily, there was a pressing need to minimize disruptions during the surveying process. DCMS executed the scanning during off-peak hours and implemented rapid scanning techniques, allowing them to gather crucial data without significantly impacting commuter traffic.

Complex Underground Geometry

Metro stations typically feature intricate underground structures that can complicate future modifications and renovations. The unique geometry requires highly accurate data for effective changes. LiDAR surveying proved invaluable in this context, as it captured the complex layouts in great detail, which was essential for:

• Facilitating Future Modifications: Accurate data enables easier planning and execution of upcoming infrastructure projects.

• Ensuring Safety Compliance: Comprehensive structural data assists in maintaining safety and compliance with regulatory standards.

Remote Collaboration Needs

The challenges presented by recent global events have fostered a shift toward remote collaboration. Ensuring that stakeholders had access to real-time data and visualizations became crucial. DCMS employed a Matterport digital twin to facilitate remote access, allowing stakeholders to explore the scanned areas virtually. This approach allowed for efficient reviews and informed decision-making without the need for in-person meetings.

Deliverables from the LiDAR Surveying Project

The comprehensive results of the LiDAR surveying project provided the TTC with several valuable deliverables, crucial for informed infrastructure planning

• High-Density LiDAR Point Cloud Data: Capturing detailed spatial accuracy essential for structural analysis and decision-making, enabling a deeper understanding of the existing conditions.

• Georeferenced Orthophotos: Providing mapped site references that enhance location awareness and contextual understanding for planners and engineers.

• Virtual Matterport Walkthroughs: Allowing stakeholders to explore the stations virtually, facilitating collaboration across teams and enhancing engagement amongst project participants.

The Technology Behind LiDAR Surveying

DCMS harnessed advanced LiDAR technology to collect millions of spatial data points across the three underground stations. The high-resolution point cloud data was carefully processed, enabling comprehensive infrastructural analysis and supporting future upgrades.

Tools Used

• Leica RTC360: Renowned for its precision and speed in capturing 3D environments, this tool was crucial for obtaining accurate scans of each station.

• Autodesk ReCap: Used for processing point cloud data, it helps convert raw data into formats suitable for analysis, modeling, and visualization.

• Matterport Pro3: Leveraged to create immersive digital twins of the stations, allowing for virtual tours that enhance understanding and collaboration.

Need Accurate LiDAR Surveying for Urban Infrastructure?

The demand for precise documentation and effective planning solutions in urban transit systems continues to grow. DCMS remains committed to providing the best in LiDAR surveying technology and expertise.