Trial and error is never a good approach when it comes to flood preparation.

With Hurricane Earl lumbering toward the East Coast with the possibility of turning back into a Category 4 storm, some might be wondering what kind of precautions they should be taking.

The city’s Department of Emergency Management has the resources to help.

Geographic information systems — also known as GIS — is traditionally used by city departments ranging from economic development to public works to make decisions on issues ranging from zoning to street paving. But it can also help administrators and citizens learn what they need to know to avoid disaster.

“It’s one of our greatest planning tools,” said Capt. Jim Judkins, Suffolk’s emergency management coordinator. “It has different uses in different departments, but it can tell us if a certain area — even a certain house — will flood depending on what hits.”

GIS consists of an electronic database of the physical features that currently exist in the city and the software to interpret the database.

The technology was first put to good emergency management use during Hurricane Isabel, Judkins said.

“At that point, it was a one-person staff,” he remembered. “I begged his boss to let him come out to the emergency operation center, because I knew the value the data could have. Once he started creating information and maps, he was there from then on. They can track road closings and downed trees. It’s unlimited.”

Among the things the technology has helped create in Suffolk are a map of the city showing areas prone to hurricane flooding and a list of road segments subject to flooding. Both can be found on the city’s website under the Emergency Management area in “Flood Info.”

Judkins said he can also look up any given address and show a resident how much a location would flood, depending on the category of storm.

“A picture is worth a thousand words,” Judkins said.

The data collected during a storm is added to the GIS database, which allows city officials to update everything from flood maps to evacuation plans.

GIS data is also used in a program called HURREVAC, which emergency management uses to track a storm. The program can show the current track of the storm, what areas are under watches and warnings, when to expect high tide and winds and color codes different areas surrounding the storm to depict the level of intensity it will have when it hits a given area.

“A lot of things change, but if the storm continues its current path this shows us that it will hit Suffolk with tropical storm force, and we could see winds at 39 miles per hour at 2 a.m. on Friday,” Judkins said as he looked at his screen on Wednesday.

For questions call Judkins at 514-7586.