Mapping disasters with geo-tagged photos
Although photo-mapping is commonly used to document the locations and conditions of assets, some city and county governments are finding that the technique along with GPS-enabled digital cameras can quickly and accurately assess property damage after natural disasters. Officials in Accomack County, Va., and Webster County, Mo., say it is the most efficient way to collect the data needed to apply for federal assistance after storms. Fargo, N.D., also has found that photo-mapping minimizes fraudulent reimbursement claims following floods.
Photo-mapping expanded beyond the domain of GIS professionals a few years ago when manufacturers such as Ricoh developed digital cameras with built-in GPS chips. The cameras tag each photo with GPS coordinates of the picture’s location, along with time and date.
Documentation for disaster aid
On August 27, 2011, Hurricane Irene skirted the U.S. East Coast, leaving a trail of damage from Florida to New England. With an intensity reaching Category 1, Irene ranks among the costliest storms in U.S. history. Located east of the Chesapeake Bay, Accomack County, Va., was spared the brunt of the storm. Although many low-lying areas across the county were under water, no lives were lost, and property damage was not severe.
Having weathered many hurricanes previously, the county was prepared to deal with Irene and the aftermath. Its Public Safety Department’s Emergency Management Division spearheaded disaster preparation activities as Irene approached. One of those efforts positioned Accomack County to quickly gather the information needed to qualify for federal disaster assistance after the storm.
Beginning in 2007, the agency used government grants to purchase GPS-Photo Link photo-mapping software from Thornton, Colo.-based GeoSpatial Experts and nine GPS-enabled Ricoh cameras. The software automatically correlates coordinates from hand-held GPS units and digital photographs. It maps photo locations on GIS layers and digital maps, and then creates a variety of reports.
The cameras also can record attributes of items being photographed. A keypad on the camera allows the photographer to enter information or select from pre-populated drop-down lists. The attribute data is permanently attached to its associated photo.
“We bought the cameras with the idea they would be deployed for damage assessment after storms and other incidents,” says Jason Loftus, Accomack public safety director. “But we also recognized operational uses to collect information for other applications.”
Accomack used the GPS cameras and photo-mapping software to capture information after several isolated emergency incidents, but Hurricane Irene was the first emergency that required their use county-wide, and the information was helpful in applying for federal disaster assistance. “We’re responsible for getting property damage data to the state within 72 hours, which means we need boots on the ground in 24 hours,” Loftus says.
Race against the clock
The state must act on behalf of its counties to request federal emergency aid, which comes in many forms, including low-interest building loans to residents and direct payments to local governments for infrastructure repair. The federal government determines the minimum dollar amount of damage that must be reported within a particular county to qualify for assistance, and the level of financial assistance corresponds to the severity of damage.
Once a disaster occurs, a county is in a race against the clock to document enough damage to exceed the minimum threshold, Loftus says. Photo-mapping significantly enhanced Accomack’s ability to do that.
To prepare for a big event like Irene, public safety officials used information from FEMA’s website to create drop-down data lists in the cameras so that each field inspector collected the right property information, which includes structure type, degree of damage, level of flooding and other details.
Accomack has traditionally assigned responsibility for private property damage assessment to the public safety department. But, because public safety personnel typically have other duties after a storm, it trained the county building inspectors to use the cameras and collect the field data for privately owned houses and buildings.
As soon as Irene’s winds had calmed, Accomack deployed a GPS-equipped aircraft to survey the entire county. Back on the ground, that survey was transferred to the county GIS map to determine which areas had sustained the most damage. The information was used to prioritize deployment of the inspectors.
By car and boat, the inspectors traveled to collect as much evidence of hurricane destruction with the cameras as they could. The memory cards were delivered back to the GIS department for downloading into the GPS software, where the photos and files were processed and output as an Excel spreadsheet. The spreadsheet was emailed to the County Assessor’s Office, where assessors used the photos to determine the pre-storm value of each property.
The Excel program used the property value to calculate a dollar figure based on the degree of damage recorded in the field with the cameras. That information was tallied for all private properties across Accomack County and supplied to the state for its submission to Washington. Although FEMA ultimately did not make individual assistance declarations for Accomack following Irene, county officials concluded that the photo-mapping technique succeeded in helping them capture vital information more quickly.
Even as the Excel file was being examined in the Assessor’s Office, the photographs were serving other purposes. They were uploaded and displayed as thumbnails on the county GIS maps. Officials could view individual photos to see them at full scale and read the damage reports. At a glance, the map gave them an overview of which parts of the county had suffered the most damage so that appropriate support and clean-up resources could be focused effectively.
The GIS manager used the photo-mapping software to output the photos to a Google Maps page on the county website. Residents who had been evacuated were encouraged to view Google Maps to see the condition of their homes and neighborhoods before they returned to the flood zone.
Now, the public works department is using a photomapping app, GeoSpatial Experts’ GeoJot, with iPads to document maintenance issues. Crews also will use the tablets for photo mapping damage after the next severe event.
It does not take a hurricane to put some rural roads in Missouri’s Webster County under water. Rain storms can inundate road crossings where simple concrete slabs span creeks and small rivers. In just the past few years, however, the county has used geotagged photos to receive more than $1 million in FEMA grants to replace four often-flooded crossings with new bridges. “Low-water crossings have no address, so we document their locations with geotagged photos and plug them into a map to show where they are,” says Linda Watts, Webster County assistant emergency management director.
Flooded crossings cause greater problems for the county than simply tying up traffic when the stream swells in a rainstorm, Watts says. Flood waters usually carry debris, and the floating logs and branches inflict repeated damage to the crossing and the road surface. Keeping them repaired can be a constant battle and revenue drain.
In 2008, the county purchased the same photo-mapping software and digital cameras used by Accomack County. Every time a crossing floods, someone from Watts’ office is on the scene photographing the high water and related damage. With 100 low-water crossings in the county, the location- and time-stamped photos show a pattern of repeated floods and destruction at specific places, which builds the case for bridge construction. “We can document with the GPS camera that it’s the same location [that’s flooding] over and over again,” Watts says.
Plans are under way to load the photos into the county GIS, but for now, the agency prints the geotagged photos along with a location map and sends them to the state, which must submit the grant request. To date, Missouri has successfully requested bridge-building funding for Webster County from two disaster mitigation grant programs managed by FEMA.
Preventing flood fraud
Since 2009, Fargo, N.D., has experienced unprecedented flooding from the Red River, which runs through the center of town. Over the past three years, the Fargo Engineering Department has become especially skilled at quickly building levees and sandbag embankments to protect property in and around the city.
Fargo’s policy is to pay private property owners to repair any damage inflicted by municipal vehicles when sandbags and other levee-building materials were used during a flood. “We use heavy equipment to put clay and sandbags in place, and we go into people’s yards,” Masten says. “Driving across a driveway with a front-end loader can do some damage.”
The engineering crews that erect the flood protection barriers now carry GPS-enabled digital cameras with them on each job. They take photos of every property that is affected by the temporary construction projects before and after, even if there is no damage. Back at the office, the photo-mapping software matches geotagged photos to the correct parcels in the city GIS. The documentation helps prevent against fraudulent property damage reimbursement requests.
Engineering crews also snap photos of the levees and embankments they build, and compare the photos against resulting flood damage in specific areas to assess how well the structure and its materials performed in keeping out water. As local governments begin to use photo-mapping for documenting disasters and for ordinary maintenance needs, other uses for the technology are sure to emerge.
Kevin Corbley is a geospatial business consultant.