In conjunction with the surveying activities for the sesquicentennial event of the 6th P.M., experienced and novice geocachers trekked one mile south and one mile east to the town of Mahaska, Kan., for a "Cache In - Trash Out" geocaching event on June 10, 2006.

Steven R. Thompson PE, with an Ashtech Z-12 dual-frequency, occupied the point over the stone for three hours collecting data every 30 seconds, then processed the data with the National Geodetic Survey Online Positioning User Service (OPUS).

Geocaching Explained

Geocaching (pronounced geo-cashing) is an entertaining adventure game for GPS users. People set up hidden treasures called caches all over the world according to established rules posted on the www.geocaching.comwebsite. Participants use GPS coordinates to find these caches. Geocachers are asked to treat the land with respect and trade fairly: if they take something from the cache, they should leave something in the cache. Trade items vary widely from Happy Meal toys, to Play-Doh, money, CD players, or special items called "travel bugs." Travel bugs are items with tracking numbers; their travels from geocache to geocache are documented, mapped and measured. For a geocacher, the most valued of these hitchhiking items is the geocoin, a rarely found trackable coin, custom-minted to express various themes.

Steve Brosemer as General Calhoun in period costume.

Geocaching at the 6th P.M.

Near the Mahaska area, local geocachers released a few permanent geocaches especially for the event. In addition, Steven R. Thompson, PE, and I spent an entire day before the anniversary event placing 50 temporary geocaches. These were hidden for attendees to try out geocaching skills, and we took care that even the youngest attendees would be able to get to them. Each geocache entitled the finder to one Sacagawea gold dollar. Experienced geocachers brought their own handheld GPS units, while those trying for the first time were able to borrow a Garmin eTrex Legend GPS receiver to guide them to hidden riches. "I found it!" was the happy cry of many of the children present for the day. Several surveyors learned about geocaching as they followed their children on the hunts for gold.

While hunting, the geocaching participants carried trash bags to police the area as part of a Cache In - Trash Out environmental event. Glen Soldan, Salina Police and administrator for Kansas, brought an amazing display of 119 different geocoins to share with attendees, six of which he gave away to winners of a drawing. Charles Britton, geocaching along the path of Lewis and Clark, provided three geocoins to give away. Dick Kloke, president of Nebraskache, gave away a Nebraskache geocoin during the drawing. Many other travel bugs were exchanged to get them into new hands.

That day, surveyors learned about geocaching, and geocachers learned about surveying. Richard Iman, CILS, senior party chief for the Survey Department of Leavenworth County, Kan., and a certified counselor for the Boy Scouts of America Surveying Merit Badge, presented a display of surveying equipment and explained the use of tools ranging from Burt's solar compass and Gunter's chain, to slide rules, to modern GPS equipment. From this presentation, geocachers learned how the sport and use of the latest technology is grounded in the work of surveyors many years ago.

The memorial marks the the initial point of the Sixth Principle Meridian of public land surveys.

Teaching Children to Geocache

The highlight of the event for me was the chance to work with some of the children who attended the event. After lunch I had to go to my car, so I thought I would check on a spot where one of the event geocaches was hidden. Sure enough, I saw that it was still there; no one had found it yet. I got to my car, noticed the batteries in my GPS receiver were low, changed the batteries for fresh ones, and headed back to the building with the GPS receiver running. As I walked over the still-undiscovered geocache, I pressed a button on my Garmin eTrex Legend to get the coordinates.

As I approached the front door of the community center, a friend of mine, Pat Ryan LS, KS, TN, a surveyor for Professional Engineering Consultants in Topeka, Kan., came out with his son Joseph (age 11) beside him. He was told that I would show his son how to geocache. "Sure!" I said. Luckily, I had fresh batteries and coordinates in my hand that would lead them to a geocache that I knew was still hidden. I prepped the receiver and let Joseph have it. And away he went, following the arrow and watching the numbers getting smaller and smaller. I stayed back to watch from a distance. Dad and son walked over the geocache twice before they discovered the film canister hidden between the edge of the sidewalk and the grass. Joseph plucked it from the spot, turned around to face me, and, while holding the geocache high in the air, he yelled, "I found it!" It wasn't until after I got home to recount the story with my family that I discovered that this geocache was the last one!

As I watched from a distance, another surveyor came out looking for me. Tricia Robello LS, deputy county surveyor for Sedgwick County, Kan., introduced me to her son Caleb. Caleb also wanted to geocache. After my receiver was returned, Caleb looked for four different sets of coordinates from my list of unclaimed numbers. He was pretty good with the Garmin receiver. He zeroed in on every spot, but came back emptyhanded each time. Since I had helped hide every geocache, I knew that some geocaches were missing. Somebody had yet to approach me with the finds. While Caleb pursued his attempts, another boy joined us, waiting for his chance to try geocaching. With only one coordinate pair left to search, Caleb chose to step down and hand the Garmin receiver over to the other boy for the last set of coordinates. "That was an honorable thing to do," I told him. "You know what? For finding where those geocaches were supposed to be, you win a gold dollar." Caleb proudly walked off with his trophy and with knowledge of how to make use of those billion-dollar satellites floating in space.

The last boy, Seth, 6-year-old son of Todd Burroughs, LS, also wanted to try out the GPS receiver. We plugged in the very last set of coordinates, which pointed to a position about two blocks away on the other side of a busy street. "We're going to have to get permission from your mom or dad before we can go that far," I said. He replied that his dad was in a meeting. I thought to myself, "This is where I'm supposed to be." Having seen the wonderful presentation from Steve Brosemer and Jerry Penry before-twice-I knew what I was missing. Seth was more important now. We found his mother on our way to the community center, and we wandered off, following the arrow on the receiver. After coming up emptyhanded on the last available set of coordinates, I told him, "That was the last set of coordinates. There are no more coordinates left; but you did find where it was supposed to be. Do you know what that means?"

He knew. He smiled, held his hands out, and said, "I win!"

"That's right!" I said, and gave him his very own Sacagawea gold dollar. We trekked back and found his mother. He stayed to tell his mom all about it, while I went inside and caught the tail end of the speech.

This was the first time KSLS had incorporated geocaching with one of its events-but it certainly won't be the last.