Bronze disks, over a million of them, are permanently set in the National geodetic network across the country. Many can be found locally. So what are we talking about here?
The U.S. Department of Commerce National Ocean Survey, formerly the Coast & Geodetic Survey, has determined with great accuracy the latitude and longitude and or elevation of thousands of locations across the country of these markers. At many points, a bronze marker is embedded in cement or bedrock. About a million of these “monuments” make up the network.
The bronze disks measure about three and a half inches across. On their face are survey points for latitude and longitude, elevation, gravity, and azimuth or direction.
The markers were and are still used by engineers, surveyors, and mapping agencies as the basis of maps, charts, and boundary surveys and for a variety of additional projects.
Over time, the face of the bronze markers has changed in appearance, yet the information contained on the marker remains the same. The marker shown in the photograph was set atop a 12-inch cylinder of concrete extending three inches above the ground. The marker was set in place in 1967. Nearby, a “whiteness post” indicates the monument is nearby. An additional monument is located 71.6 feet away on a cylinder of concrete 5 inches above the ground.
The system of precise locations was set into place well ahead of GPS systems. However, today they remain important and accurate land markings.
Over the years the original data was “re-calibrated.” Originally the horizontal coordinates for this monument was established by classical methods and adjusted by the National Geodetic Survey in January 1999. The adjustments were then properly recorded.
While this monument is situated seemingly in the middle of nowhere, others are not. Fact is they may be closer than you might imagine.
It is possible to google search the National Geodetic Survey Data Explorer. My preference is to log onto www.geocaching.com/mark The site offers a quick and easy method to identify monuments. Within the site monuments can be located via zip code.
For example, put in the search box 16701, the zip code for Bradford, and a listing of monuments will be shown. The locations will not be shown on a map, rather as GPS coordinates.
There are twenty-five individual listings for Bradford and each has a PID designation. The folks who are called “Geocashers” use their GPS units to locate U.S.G.S. monuments and other features. And in many cases, as sites are located some record the date the site was visited and comment on what they observed.
For example, PID site MA2326 was visited a number of times and comments logged. Also, scroll down to the bottom of the page where there are directions to the site and a description of the location when the site was established.
Today, many young folks do not understand the basics when it comes to using a map and compass. But that’s where a GPS and a topographical map can help. Using the GPS to navigate to a specific location is one thing. However, combining the use and understanding of a topographical map at the same time can go a long way to opening up remote areas that otherwise may have seemed to be inaccessible.
Early on, topographical maps and a compass opened the doors to a wide variety of areas. Armed with a topo map and a compass unfamiliar areas could be explored with relative ease.
While the basic map and compass can still be used, the GPS provides more latitude in learning the lay of the land. Besides, kids today enjoy using all kinds of different electronic devices.
So why not take advantage of the situation and use what works best to help the younger generation learn woodsmanship skills?
And while you’re at it, be sure to include a few sessions using a compass. After all, it’s one device that doesn’t need batteries.
Frankly, I enjoy using both a GPS and a compass. At least with the compass I have a backup plan.
(Charlie Burchfield is an active member and past president of the Pennsylvania Outdoor Writers Association, an active member of the Professional Outdoor Media Association, Outdoor Writers Assoc. of America and the Mason-Dixon Outdoor Writers. Gateway Outdoors e-mail is GWOutdoors@comcast.net)
