How 3-D Mapping Technology Could Improve Firefighter Safety

When a fire breaks out inside a large structure like a mall or office building, firefighters are often at the mercy of blueprints or hand-drawn sketches to figure out the safest way to navigate the smoke-filled corridors.

In Memphis, officials envision a new approach using light detection and ranging, or LiDAR, technology to create 3-D maps for first responders.

Researchers working on the new building mapping project said law enforcement and firefighters could both benefit from the technology, which would not only help them navigate unfamiliar structures but also enable agencies to track first responders’ movements inside the buildings.

Funded in part by a $450,000 grant from the National Institute of Standards and Technology (NIST), Memphis is one of three cities engaged in a research program to test and refine LiDAR capabilities. The city contributed approximately $400,000 to the effort as well.  

Working with the University of Memphis, the city deployed 3-D mapping technology to scan the interior of seven large buildings, including the National Civil Rights Museum, Liberty Bowl Memorial Stadium and Benjamin L. Hooks Central Library.

“We are creating digital 3-D models of the buildings and we’ll be providing that to the first responders so they can become familiar with the space without actually having to go visit,” said Mike Rodriguez, chief information officer of Memphis.

While LiDAR has proliferated recently, such as with its use by autonomous vehicles, the technology has not been deployed much for mapping indoor spaces. But those involved in the Memphis project believe it could revolutionize emergency response capabilities.

“A map is only good if you know your position relative to the map,” said Chris Wilson, a division chief with the Memphis Fire Department. “I think that once it gets locked down and refined, it will truly change how we fight fires or even respond to medical calls or how police officers respond to calls.”

Rodriguez believes the data could eventually be used to pinpoint and locate people inside a large complex during an emergency.

“Let’s say you are in room 305 and there’s an active shooter going on. You call the police and say ‘I am in room 305.’ That really means nothing to them,” Rodriguez said.

With the mapping data, Rodriguez envisions first responders being able to find room 305 on a map and create a route through the building that gets them there.

“We can actually upload a route to the police officer or fire department to show them the path they need to follow to get to that room,” he said.

It could also be used to keep first responders safe by providing for a way to track them inside of buildings. Wilson said firefighters could be outfitted with trackers that would show up on the maps, or incident commanders could use map data to guide responders inside the facilities. 

Across the country, 25 firefighters died on the scene of fires in 2018, including 13 lost at structure fires and 10 at wildland fires, according to the National Fire Protection Association.

“[Firefighters] typically don’t have good building information at all,” said Jeb Benson, who is overseeing the location-based services research within NIST’s Public Safety Communications Research Program. “Pre-incident planning is not something that every department has standard operating procedures for.”

How 3-D Mapping Works

To create 3-D maps, researchers from the city and university are combining data collected by LiDAR scanners and 360-degree cameras deployed inside the seven buildings. The LiDAR scanners work by sending out infrared signals that can be used to gauge distance to an object. Each individual signal results in the creation of a point that can be plotted and combined with thousands of other scanned points to create a 3-D map.

Compared to floor plans, the LiDAR scans will capture the location of desks, partitions, or displays inside the buildings and provide “a much more accurate picture of what the space looks like,” Benson said.

While useful for first responders, the creation of the maps themselves was not the ultimate goal of the research, Benson said. Researchers plan to create and release annotated datasets that others can use to advance and refine the technology. 

One of the ways Memphis researchers are already experimenting with the data is through the development of computer algorithms that scan the resulting maps and automatically identify and tag items of interest. In the case of firefighters, that could mean tagging each door and window, utility shutoff, or fire extinguisher.

“We process the video data using machine learning techniques to identify all the objects that are relevant to public safety,” said Lan Wang, the chair of the computer science department at the University of Memphis.

To capture the data, researchers wore backpacks outfitted with cameras and LiDAR scanners that enabled them to collect the data as they walked through each room in a building. Depending on the size of the building, each physical scan could take several days, Wang said.

Once the images and scans were collected, researchers at the university worked to merge it all together to create the usable 3-D maps and to tag the items of interest in each building. Researchers manually tag some items, like doors and windows, in order to cross-check the accuracy of computer algorithms designed to automatically tag the items of interest, Wang said.  

What’s Next?

Memphis has scanned approximately 1.8 million square feet of indoor space as part of the project.

Combined with the two other NIST grant recipients—Hancock County, Mississippi and Enfield Fire Department in Connecticut—the three entities are collecting LiDAR scans of 29 buildings and 4.5 million square feet of space.

Once the data from the projects is cleaned and analyzed, Memphis plans to share its findings and select parts of the data through its open data platform in November. The data has already been handed off to the city’s geographic information system (GIS) team to begin building 3-D digital models of the scanned buildings. Rodriguez said security concerns will prevent the city from sharing all of the raw data, but the city will be able to provide some information to researchers that they can build upon.

Wang said university researchers fine-tuned their own scanning process based on their experiences collecting the data. 

For example, when trying to scan small indoor spaces like closets, she said the team had to skip the backpack scanners and build their own handheld devices in order to obtain more accurate scans.

“There is a lot of work on surveying outdoor space but not much on indoor mapping,” Wang said. “I think what our project can produce is a process for other people who want to do the same thing.”