Memphis 3D mapping project charts the future of emergency response

TML Communications Specialist

A new project is utilizing 3D mapping technology to help emergency officials in Memphis respond, plan, and train for situations involving several important sites in the city.
The project is funded through $450,000 grant from the National Institute of Standards and Technology (NIST) as one of three municipal projects to research, test, and refine LiDAR capabilities. The city of Memphis also contributed $400,000 toward the project.
Researchers from the University of Memphis worked with emergency management and city officials to develop 3D maps of seven important buildings in the city including the National Civil Rights Museum, Liberty Bowl Memorial Stadium, Benjamin L. Hooks Central Library, and Pink Palace Museum. The project also mapped locations on the University of Memphis campus including the FedEx Institute of Technology and Wilder Tower. The goal for the project is to scan and process more than 1.7 million square feet of space.
Lan Wang, department chair and professor of computer science for the University of Memphis, was one of the project leads and said the buildings mapped were chosen for a variety of reasons.
“The main criteria for us was the public interest in the building and whether that building is of interest to public safety entities,” Wang said. “The Pink Palace Museum and National Civil Rights Museum have a lot of important and historical artifacts so it would be very important to save those buildings. The Liberty Bowl Memorial Stadium is a very important building to protect, especially since a lot of people might be there at one time. For the university, the FedEx Institute of Technology is definitely something we are interested in protecting. The Wilder Tower is probably the tallest building on campus, and if there were an incident in the building, it would present some challenges to public safety agencies.”
The 3D maps employ LiDAR technology, which refers to its use of light and radar technology and can also be an acronym for “laser imaging, detection, and ranging.” Eddie Jacobs, electrical and computer engineering professor at the University of Memphis, said the project used this technology to provide laser-accurate measurements for 3D map generation.
“LiDAR basically uses light to measure distances,” Jacobs said. “We use a laser that scans around and measures the distance from where the laser is to points in space that the laser reflects off of. We get 15 frames a second, which means every fifteenth of a second we get all the data points within a 360-degree circle of where you are.”
Wang said the university used a LiDAR backpack and a 360-degree camera to capture 360-degree images using a “point cloud.” A point cloud is a collection of 3D data points, usually defined by x, y, and z coordinates. These tiny data points can then be used by 3D modeling technology to recreate physical spaces for purposes including planning, architecture, and virtual reality programs.
Since the data collection can be sensitive, Wang said the person collecting the data has to walk through a room at a certain pace. The mapping program also allows the labeling of certain items.
“Typically, each floor needs its own scan, but for bigger buildings we often break down each area of a floor into separate sections,” Wang said. “Afterwards, we have the point cloud data and images. We have to piece the multiple scans back into one big point cloud. We also process the images to label objects. We then combine those back together into an annotated, color-coded point cloud. We can use georeferencing to add geocoordinates to every point in the space. We recognize 30 types of objects like fire extinguishers, fire alarms, stairs, elevators, windows, and doors. Anything that is relevant to public safety agencies is labeled. We actually asked officials what objects they felt would be most important for us to label, and they ranked the importance of different objects.”
Part of the process of combining the scans, images, and other information is removing things not necessary for the 3D map like people who may have been in the building when the scan was conducted. Different objects and room sizes can also impact data collection.
“Scanning can be very tricky,” Wang said. “There are a lot of things you should do and shouldn’t do. You have to keep all the doors open and make sure people are not moving. There are a lot of details you have to pay attention to. Small spaces can be more difficult, like storage rooms or equipment rooms. Stairs and rooms with lots of windows and mirrors can be hard to scan because of reflection, but we are able to deal with all of that. Through the process, we learned a lot and created a best practices document. From the data processing side, one of the big surprises is that we couldn’t find many existing data sets that had the objects we wanted to label. We had to build our own data sets, which takes time and manual labor.”
Beyond real-time response to emergencies, Wang said there are a variety of ways in which the scans can be used.
“It can be used for training and for planning purposes,” she said. “For example, if you wanted to plan the best rescue route or how to navigate through the building before entering it, you can use this model for planning. A lot of our emergency personnel are interested in finding the best entrance to use if they need to reach a certain location in a building. That can save time in an emergency. The model can be used in virtual reality simulations as an environment for training. It’s also possible to use the technology after an emergency. If an area is a destroyed, you can use this scan to recreate what was there.”
Wang said 3D mapping technology like that being used in Memphis is also currently being used to reconstruct the Notre Dame Cathedral in Paris after the massive fire in 2019.
“I think this will become more common as the technology becomes more widely available,” she said. “As the technology becomes easier to use, I see the 3D mapping being used in a variety of ways.”
While all the buildings set out in the initial project have been scanned, there is interest in continuing the project if funding becomes available. Wang said Memphis officials have expressed interest in 3D mapping of Memphis area schools in the future because of the need to protect those structures.
The data sets collected during the current project will be provided through the city of Memphis’ website for those who need the data for research projects, public safety initiatives, and to give feedback on the project so future scanning projects in the city can be refined.
Memphis Deputy Chief Information Officer Wendy Harris said the mapping project is another example of how working together can benefit both the city and the university.
“From a research perspective, the University of Memphis has the facilities to provide students with the knowledge and skillsets to assist in these types of projects,” Harris said. “The city, on the other hand, always likes to work with local businesses and entities on these types of projects. It’s a benefit for both to use our resources to get more done. We don’t have to go through a lot of red tape to work with each other. There is great expertise on both sides.”
Jacobs said university officials always welcome a chance to help the city where they work and live.
“As both members of the University of Memphis and individuals that live in Memphis, the city of Memphis is a city on the ascension,” he said. “We are improving in a lot of ways. This is a way we can directly contribute to that. The university is very supportive of the city of Memphis, and as individuals who live here, we at the university like doing these kinds of things for the city.”