When Hurricane Helene swept through Florida, emergency managers were unable to procure imaging due to cloud cover that grounded aerial imaging. Instead, they had one consolidated source of imagery to rely on: #PhotoMappers. It's a moment that underscores both the stakes and the significance of a volunteer-driven GIS effort that has quietly become an essential piece of disaster response infrastructure.
The People Behind the Maps
Tari Martin is the Chief Geospatial Information Officer with the National Alliance for Public Safety GIS Foundation (NAPSG) and has been with the #PhotoMappers effort since its launch in 2017. Erin Arkison chairs the GISCorps Disaster Response Subcommittee, joining in 2018 and helping coordinate the volunteer teams that make it all work. Together, they represent two sides of a well-oiled machine. One handles the technology and agency relationships, the other manages the volunteers.
How an Activation Works
The process often begins informally. Erin might notice breaking news and reach out to Tari, or an emergency manager will contact NAPSG directly through a shared Teams channel or group email. From there, the first question is always: do we have the capacity?
"We don't want to activate if we don't have the people and the manpower to support it," Tari explained. Once Erin checks availability with the admin team, a core group of about 15 specialized volunteers, Tari submits a formal volunteer support request and the activation begins.
On the technical side, NAPSG clears previous data, repositions the maps, and opens the photo queue. The admin team begins vetting incoming images while Erin’s group monitors the workload. If the incident looks like it will last more than a few days, the activation is opened up to all #PhotoMappers - a pool of 700 volunteers.
"It's a little bit of a gut feeling," Erin said of that decision. "You kind of gauge it based on how many photos are coming in, what's being mapped, what the availability is."
As photos flow in, Admins shift from mapping to vetting. They become quality control, leveraging their experience to ensure every image that reaches an emergency manager meets the team's standards. The activation follows the disaster, sometimes literally, as with Hurricane Laura, when the team tracked storm impacts from Louisiana all the way up to New York City.
Deactivation is just as deliberate. Tari stays in close contact with the requesting agencies, monitoring when aerial imagery starts to come in. If it's clear and comprehensive, #PhotoMappers stand down. If it's clouded or incomplete, they keep going. Volunteers then log their hours and, if eligible, receive certificates that count toward their GIS Professional (GISP) credentials.
What Emergency Managers Actually Do With the Data
The use cases go well beyond what many might expect. Tari has heard from FEMA teams who used #PhotoMapper data to jump-start geospatial damage assessments before other aerial assets could get airborne. Search and rescue teams have used it to understand what they're walking into. USGS has also used the imagery to guide field operations. Water authorities have drawn on it, too.
In one notable case, #PhotoMapper images helped support disaster declarations for counties in Georgia following a hurricane. "I don't want to say we were the only game in town," Erin said, "but it definitely helped guide that."
The most recent activation came in March, when severe flooding in Hawaii destroyed USGS water gauges, the instruments typically used to direct teams collecting high-water marks. Without that data, USGS turned to #PhotoMappers, activating them several days after the incident to document evidence of flooding. It was an unusual timeline but a clear signal of how adaptable the program has become.
In Their Own Words: Agencies Respond
The program's impact is perhaps best captured in the words of those who've relied on it.
Pennsylvania Emergency Management summed it up plainly after one activation: "Some of the damage from this storm occurred in a county with minimal full-time emergency management personnel, so they have been working overtime to assess the aftermath. We were able to find an area with significant damage because of #PhotoMapper, and deploy personnel there to help the residents recover."
During Hurricane Idalia, the recognition came from multiple directions at once. #PhotoMappers was highlighted on the Florida State Geospatial Coordination Call, and during that same call, South Carolina mentioned they were actively monitoring the platform as they awaited impacts to their own state. On FEMA's Geospatial Coordination Call for Idalia, the FEMA Response Geospatial Office confirmed they were already using #PhotoMappers as one of the few available imagery sources for conducting Geospatial Damage Assessments. The program was later highlighted on FEMA's internal Geospatial Working Group call as a "trusted and valuable resource," with attendees encouraged to check it out.
A Team Effort, Through and Through
Both Tari and Erin are emphatic that #PhotoMappers' success belongs to everyone involved: NAPSG, GIS Corps, the Admins, and the hundreds of volunteers who contribute from wherever they happen to be.
"#PhotoMappers would not be anything without GIS Corps, without the admins, without the 700 volunteers," Erin said. "It's very much a team effort."
For those interested in joining, it's accessible. US-based GIS volunteers can sign up through the GIS Corps website. No boots required, past volunteers have mapped disasters from their kitchen tables in pajamas.
"It's really rewarding," Erin said, "especially when you get those little soundbites and you know that the dashboard is up at the NRCC and you're like - wow, that's our data."
