It wasn't a typical 911 call: last fall, a horseback rider wandered into Whitetail Woods Regional Park and became lost. Then his horse fell through a boardwalk and got stuck in the mud.

The caller reported his location using an eight-digit number found on a nearby trail post. First responders located him quickly and saved the horse, said Randy Knippel, geographic information system manager for Dakota County.

For Knippel, it's a success story demonstrating the value of emergency location markers, a system he's encouraged county parks to implement.

Two Dakota County parks are among the first in the state to be outfitted with the markers, blue signs that display eight numbers corresponding to a national grid system. They aim to help emergency responders find lost or endangered hikers more quickly by providing a precise, easy-to-understand location.

The emergency location markers use the U.S. National Grid, a coordinate system originally used by the military that's gradually becoming more popular. Eventually, some mapping experts — like Knippel — believe the network should replace latitude and longitude in emergency situations.

"We're on the leading edge when it comes to this," said Steve Sullivan, Dakota County parks director.

The county installed the small blue signs on all trail intersection posts in Whitetail Woods when the park debuted in fall of 2014, and on 47 miles of trails in Lebanon Hills last September, said Knippel. Each sign costs $35, and affixes to existing trail posts. There are 17 in Whitetail Woods and 40 in Lebanon Hills. Next up is installing them on mountain bike trails, he said.

A handful of other cities have the signs in their parks. St. Paul's Lilydale Park has them, a move spurred by the difficulty first responders had in finding children there during a 2013 landslide, he said.

For those advocating wider use of emergency location markers, the key to their usefulness is reliance on the U.S. National Grid, now also adopted by the Federal Emergency Management Agency (FEMA).

Longitude and latitude have been the standard in describing geographic location. But the system has flaws, said Knippel. With its minutes, seconds and decimal points, it can be confusing for someone unfamiliar with it.

The grid is straightforward, advocates say, and there are cellphone apps anyone can use to find their grid location if there are no signs.

"I think the great thing about the National Grid is it's simple to read. If someone's in trouble, they can read us a series of eight numbers and I know where they are … within 10 meters," said Mark Erickson, chief of operations for South Metro Fire Department. His department has trained all first responders in the system, Erickson said. Dakota County special operations staff know it, too.

But will it catch on? Enthusiasm seems to be building slowly. "I hope it does," said Erickson. "I think really to get it to catch on we really need the cellphone companies to use it as their standard data."

Sara Butruff of Lakeville visited Whitetail Woods for the second time last weekend, but she usually hikes in Lebanon Hills.

"I didn't really feel like you could get lost [here], but I think it's actually brilliant," she said.

But Stephen Olson is a skeptic. His family donated the land that's now Whitetail Woods. If someone gets lost, they can always look up and use the flashing light atop a nearby radio transmitter as a landmark, he said.

"A compass is still the most useful way of finding your way around," he said.

Erin Adler • 952-746-3283