High-accuracy Manhole GPS Data Collection and Invert Measurement
case study: sanitary and storm maintenance hole survey
City of Markham, Ontario
The City of Markham (population 330,000) is located to the southeast of York Region and boarders Toronto to the south. Andrews.engineer was retained by the City of Markham to carry out survey of approximately 250 sanitary and storm maintenance holes. The project requires centimeter accuracy GPS points data collection and high-accuracy rim to invert measurements for the manhole structure and any associated manhole connections.
This data collection includes the following activities:
- Pre-inspection data preparation and planning
- Field GPS data collection utilizing centimeter accuracy GPS units (Trimble Geo7x)
- Rim to invert measurements for all associated connections within each manhole
- Field data verification and validation
Due to the high-level of accuracy requirement, Andrews.engineer used specialty tools and developed techniques to accurately measure sewer depth without performing any confined space entry. The collected data is verified by calculating the slopes of all associated pipes, and results that are beyond reasonable range will be discarded and data would be collected again. Our collected data are proven to be accurate and can be relied upon for modelling practices. Andrews.engineer successfully delivered all the prescribed work by the end of 2016.
|client:||City of Markham|
High-accuracy GPS data collection & Invert Measurement
Internal data validation and assurance to ensure accuracy