When René Compean took a photo of his soot-stained legs hanging over a waterfall of steep rocks, he feared this would be the last photo he would take. Desperately lost on a hike in Southern California, he thought he might die.

“I’m not ready,” the 45-year-old told himself as he repeatedly shouted for help and used charred sticks to write SOS on any open surface he could find.

Compean had walked the Angeles National Forest hangs out more times than he could count, he said, but after venturing out onto a new path on April 12 – for what he intended to be a two-hour outing – he got lost.

Several hours after starting the solo hike, after many unsuccessful attempts to find his way around, he was scared. The temperature was dropping rapidly over the remote and rugged terrain, and the winds were blowing.

Compean grabbed his cell phone, which had less than 10% battery remaining, and climbed to a spot where he was able to get at least one signal bar.

“SOS. My phone is going to die. I’m lost, ”Compean sent to a friend, along with two photos showing his whereabouts – though only one has passed. It was the image of his legs.

The photo offered minimal information and, given Compean’s lack of a cell phone signal, the resolution was very low. More importantly, Compean didn’t realize his location settings were turned off on his phone.

Still, the grainy image was somehow detailed enough that a stranger could decipher the exact location of the hiker.

Ben Kuo was working from his home about 60 miles away in Ventura County, Calif., When he came across a tweet of Los Angeles County Sheriff’s Department, with the photo of Compean’s legs.

The sheriff’s search and rescue teams had already spent the previous night unsuccessfully searching for Compean, so they released the photo to the public hoping someone could help them.

The department tweeted, “Are you an avid hiker in the Mt. Waterman Zone? SAR #LASD teams need help locating a #missing hiker. “

Kuo, 47, inspected the image and thought, “I bet I could find this place,” he recalls.

Kuo works in the tech industry, but he is also an amateur radio operator. For several years, as a hobby, he has used his Twitter account to alert the public to natural disasters. It regularly examines satellite images to identify and track local forest fires.

Plus, he has another unusual hobby: “I’ve always liked looking for where photos are taken,” Kuo said. He frequently tries to identify where scenes from movies, TV shows or commercials have been shot. He often succeeds.

So when he stumbled upon the blurry image of Compean’s legs surrounded by an endless landscape of rocks and vegetation, he instinctively pulled out a satellite map. Because the Sheriff’s Department said Compean’s car was found near Buckhorn Campground, they limited their search to the surrounding area.

The first thing he noticed in the photo were patches of greenery. “I realized it had to be on the south side because there aren’t really any green valleys on the north side,” he explained.

This discovery helped him focus on an area that closely resembled the terrain in the image. The last step was to cross the original photo with Google Earth and compare specific details.

“By entering the time and date the photo was taken, you can compare the view in Google Earth,” Kuo said. “They matched.”

He shared a screenshot satellite images on Twitter and called the sheriff’s department to inform officials of the contact details he discovered.

After verifying the findings on information they gleaned about Compean’s whereabouts, the ministry dispatched a helicopter search and rescue team to the area.

Rescuers found Compean within a mile of Kuo’s planned coordinates.

“It was very gratifying that he was saved,” Kuo said. “If you have any information that could help save someone, this is something worth sharing.”

For Compean, who had spent more than 27 hours alone in the desert, hearing the helicopter vibrate above him left him in tears. He was overwhelmed with relief, he said.

“I am safe!” Compean, who suffered only a few minor cuts and scrapes, did not repeatedly yell at anyone in particular.

Compean’s story would likely have ended in a very different way, said Sgt. John Gilbert, of the Los Angeles County Sheriff‘s Department, was a total stranger with strong satellite skills and a keen eye for detail who did not take immediate action.

After his rescue, Compean, who works as a mechanic, thanked Kuo profusely on a Zoom call, saying, “I owe you my life.”

“I’m so lucky that Ben did what he did,” said Compean, who plans to meet Kuo for a festive meal soon. “I’m grateful to be alive.”