Benchmark Hunting
What the heck is Benchmark hunting?
Benchmarks are permanently fixed metal disks found at various locations all over the United States . These disks are used by land surveyors to perform efficient surveying, engineering and mapping . Benchmarks are actually control points used for precisely establishing an elevation or location in latitude and longitude . Benchmarks were first used in the United States in 1807 when president Thomas Jefferson Established The National Geodetic Survey, our Nation's first civilian scientific agency.
I enjoy finding benchmarks because I'm usually traveling to a place I have not been and sometimes the places benchmarks are found have some historical value. The photograph below was taken in Leadville Colorado. I found this benchmark set in a windowsill of a very old building in the center of town. A group of surveyors were working on the corner as I was looking for this disk. They were very excited to explain to me how they were using the disk in their calculations, though I couldn't repeat a word of it . All thought benchmark hunting was a great hobby.
After checking out this photo and Data Sheet use the following links to view my finds and other photographs.
My Finds
The Following is part of the information contained in a NGS Data Sheet for a Benchmark
The NGS Data Sheet
DESIGNATION - P 4
PID - KL0243
STATE/COUNTY- CO/LAKE
USGS QUAD - LEADVILLE SOUTH (1994)
KL0243_U.S. NATIONAL GRID SPATIAL ADDRESS: 13SCD885450(NAD 83)
MARKER: DB = BENCH MARK DISK
SETTING: 30 = SET IN A LIGHT STRUCTURE
SET: STONE WINDOW SILL
STAMPING: P 4 1925
STABILITY: D = MARK OF QUESTIONABLE OR UNKNOWN STABILITY
STATION DESCRIPTION
DESCRIBED BY NATIONAL GEODETIC SURVEY 1958
IN LEADVILLE.
AT LEADVILLE, AT THE INTERSECTION OF 5TH STREET AND HARRISON STREET,
14.5 FEET NORTHEAST OF THE NORTHEAST CURB OF HARRISON STREET, 21 FEET
SOUTHEAST OF THE SOUTHEAST CURB OF 5TH STREET, IN THE TOP OF A STONE
WINDOW SILL OF THE BUDGET FURNITURE STORE, FORMERLY THE COMMERCIAL
BANK, 5.5 FEET SOUTHEAST OF THE WEST CORNER OF THE BUILDING, ABOUT 2
FEET ABOVE THE LEVEL OF THE SIDEWALK.
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