Three Days, One Unified County Map in Canada
For Strathcona County, a specialized municipality in the Edmonton Metropolitan Region in Canada, a smart future requires a smart roadmap—literally.
But this is no ordinary roadway map; it’s essentially a digital twin, one that includes comprehensive details about the extent, condition, performance, use and operating characteristics of every public road in the municipality.
Developed by Calgary-based Global Raymac, a survey firm that focuses on transportation, heavy civil, facility construction and energy and pipeline construction in western Canada, the digital map includes more than 400 centerline kilometers, with emphasis on the county’s largest city, Sherwood Park (pop. 75,000).
According to Steve Sharron, manager of Lidar & Bathymetry at Global Raymac, what stands out about this digital roadway network is its scope and scale at billions of points. He explained, "There is no gap in the data between missions; every run is registered to every other run. The entire road network is completely unified. It’s possibly the largest one that's ever been done in Canada or even North America to this level of accuracy."
This impressive digital asset inventory has become the foundation for planning, engineering and maintenance for the county, a hallmark of Global Raymac’s ever-expanding mobile mapping services and a clear illustration of the evolving role of surveyors in the built environment.
Maxine, with a Trimble® MX9 mobile mapping system and further customized for the demands of mobile mapping.
The Emergence of Maxine
Global Raymac first invested in a mobile mapping solution in mid-2020, recognizing emerging opportunities with advances in LiDAR for rapid asset inventory data gathering. The firm has been working primarily in Western Canada for more than 40 years and has already firmly adopted land- and drone-based laser scanners to support various jobs.
After an extensive evaluation of available mobile mapping solutions, Sharron and his team selected the Trimble® MX9 mobile mapping vehicle-mounted solution with the AP60 Dual Head IMU, the highest-grade IMU on the market.
Sharron recalled, “We did a lot of testing of the AP60’s capabilities, and we believe we could, with time, accurately model gravity with it. It is that accurate. That high accuracy allows us to deliver point clouds to millimeter accuracy. There is no mapping project that I'm afraid to take on with this system.”
He and his team mounted the MX9 to a truck, affectionately named Maxine, and added customized connections to support all the cabling and power requirements. They also incorporated additional 360-degree cameras permanently mounted and hardwired to the truck’s mapping system. Even the interior has been tailored to help the driver operate the mapping system with ease.
Once the equipment was installed, the team scanned and modeled every instrument, like the GNSS Azimuth Measurement System (GAMS) and the distance measurement device (DMI), on the truck to assure precision results.
After a month of testing and learning the MX9 capabilities, Maxine and her operators were ready to roll. Global Raymac received its first mobile mapping contract by the middle of July 2020. Since those early days, the firm has completed well over 100,000 km of road mapping — with Strathcona County’s fully registered road network providing the biggest challenge.
Beyond a Digital Picture
The requirements for the Strathcona County unified network project, as specified by the county, were tight:
• Absolute accuracy of 5 cm horizontal and 3 cm vertical with 95% assurance
• Cleaned, colorized, and classified point cloud with intensity data
• Fully compliant ASPRS LAS v1.4R15; LAS 1.4 mm resolution
• 500 points per square meter at 20 m
• Panoramic image every 10 m
• Files not to exceed 2GB
Once the spring snow melted from the streets, the survey team fired up Maxine. Using a navigator device with a planning application to route the vehicle, the surveyors worked their way through the county. In general, they stayed in residential areas during rush hours and focused on commercial and industrial areas in the evening. They could not survey at night because of the color requirements.
Over the course of three days, the operators completed six missions (two missions per day to various parts of the county), resulting in billions of points and around 44,000 panoramic images.
The data was initially processed in Trimble Business Center (TBC). The survey team used the provincial control stations and the county’s permanent base station (logged at 1hz for the duration of the survey) along with corresponding monuments to set a control network. They also mapped 1,446 manhole covers (logged as 45 RTK epochs and post-processed back to county base), then wrote an algorithm to automatically locate those manholes and calculate the standard point from the point cloud.
Over the following months, the point cloud data was classified to denote the ground, buildings, poles and vegetation, and filter out vehicles, people and even garbage cans and then broken up into 1,659 LAS/DWG 250x250 tiles, each about 2GB in size. Initial processing took approximately six months—with no corrupted or lost data.
"Mobile scanning turns the traditional survey workflow upside down," Sharron said. “Where it used to require considerable time to collect information in the field using conventional data collection methods, now the collection is pretty quick. But, given the sheer quantity of data gathered, we have considerably more work in the office to turn that data into manageable deliverables for the client. Despite the additional processing time, the results are considerably more robust."
Once complete, Global Raymac made the unified network data in the form of the LAS/DWG tiles available through a customized web viewer, enabling users to clip areas of the network from the map to perform engineering studies and schedule maintenance plans.
The success of this effort led to a second-phase maintenance project. This year, Global Raymac is extracting all of the road centerline road markings, crosswalks, curb, gutter, signage, etc. from the unified network to create a CAD deliverable for engineering design and maintenance.
Sharron added, “A unified database with this much accuracy is ideal for engineering, maintenance and planning. For example, with a few clicks, maintenance teams can find all the potholes and then quantify the volume of cold patch required to fix them or, if needed, plan for road repaving.”
Democratizing Data
"With mobile mapping capabilities, city data is vastly more democratized, accessible to multiple groups who can use it in many different ways. With the MX9, we have the ability to deliver a continuously updated, accessible digital resource with speed, accuracy and ease."
Looking ahead to summer of 2023, Global Raymac has another 40,000 miles of mobile mapping work in the books.
From a larger geospatial services perspective, Sharron sees mobile mapping as a paradigm shift for surveyors. He explained, “Traditionally, surveyors gather data in the field and turn it over as a CSV file. That data gets filed away never to be used again, largely because of the siloed nature of organizations, particularly public entities. We might do some work six months or a year later directly adjacent to the area that we previously surveyed, but that previous work is never considered.”
It’s one reason that Global Raymac is planning to invest company resources to map all the roads of Calgary.
Sharron concluded, “We know that there are multiple uses for survey-grade data in various phases of every project, particularly on large infrastructure projects. We see high accuracy mobile mapping as an essential element of emerging digital twins. It’s asset data that is beneficial to many different groups—many of whom would never have the resources to get this type of highly accurate, unified data. With mobile mapping capabilities, city data is vastly more democratized, accessible to multiple groups who can use it in many different ways. With the MX9, we have the ability to deliver a continuously updated, accessible digital resource with speed, accuracy and ease.”