The simplest survey markers are chisel marks or nails to mark the survey points. Traditionally most professional surveyors use markers that are made of stamped metal discs set in rock or concrete pillars. As a backup, markers are stacked under the ground, in case the above ground marker is disturbed or displaced. The newest line of survey markers are long metal rods that are able to be pushed deep (up to 3 ft) into the ground. After these innovative markers are placed, a special tool is used to engage a patented "root" system that anchors the survey marker into place permanently. One of the most modern uses for these markers are in setting up GPS receiver antennas but their versatility, light weight design and speedy installation has them being used in many other applications such as the marker of choice for swampy areas where using concrete is practically impossible.
Benchmark survey markers are chiseled markers that are placed into stone structures, where an angle iron can be placed across it to form a bench. They are placed by government agencies or private survey firms. Records are kept of registered survey markers in a large computer database. The height is determined by a map of other benchmarks in the area. If you have ever been to a mountain summit you have probably seen a benchmark type survey marker. It could be a large boulder at the top of the summit, at the highest point. The benchmark typically has the station name and date stamped into it, but rarely has the elevation etched on it. The names of benchmark stations are not unique and can be used over and over again. If you see one, maybe take a picture of it.
Trig points are another type of marker and are also referred to as triangulation points. These survey markers are typically found on buildings and in urban areas.
It is against the law to intentionally remove or destroy survey markers. Anyone who deliberately destroys or removes a marker will be charged with a misdemeanor crime in most states. These markers are intended to be permanent and are used by surveyors, engineers, contractors and planners for designing, the construction of a wide variety of residential, commercial and governmental projects. While concrete or some of the newer, lighter and more permanent markers are hard to remove, many older or cheaper ones are frequently moved or just disappear. This can become quite frustrating for workers who need to track exactly where an underground pipe system might be leaking or where exactly a residential lot might end.
Survey markers form a network all the way across the United States, including Hawaii and Alaska. It is estimated that there are over one million markers in place today. They are used for many residential applications but also in many major business, research and governmental applications such as the mapping of pipelines, communications grids or simply manhole covers. These markers have been being put in place since 1879 and are responsible for mapping done across the country.
To learn more about survey markers please visit our website at http://www.usmarkers.com.
