In surveying, benchmark is a survey
marker with a precisely known vertical elevation. The term
benchmark originates from the chiseled horizontal marks that
surveyors made in stone structures, into which an angle-iron
could be placed to form a "bench" for a leveling rod, thus
ensuring that a leveling rod could be accurately repositioned
in the same place in future. These marks were usually
indicated with a chiseled arrow below the horizontal line.
More enduring benchmarks may be chiseled into a wall (the
usual type in the UK) or marked by a small brass or aluminum,
steel pin, or bolt attached to a stable foundation, such as a
concrete post, bridge abutment, building, or a purpose-made
concrete block. These markers are then used as starting
points for subsequent surveys to establish the elevation of
nearby points.
The height of a benchmark is calculated
relative to the heights of nearby benchmarks in a network extending
from a fundamental benchmark, a point with a precisely known
relationship to the level datum of the area, typically mean sea
level.
Here are the coordinates to several other
benchmarks around Traverse City:
N44 45.833 W085 36.267 PL0381
Senior Center
N44 46.575 W085 38.508 PL0387
Grocery Store
N44 45.927 W085 37.249
GC4106 NGS Zoo Benchmark
N44 45.865 W085 37.257 PL0383
Jewlery Store
N44 45.882 W085 37.247 PL0384
Boardman River
N44 45.462 W085 36.470 PL0327
Library
N44 44.827 W085 33.923 PL0323
TART Trail
N44 45.600 W085 30.833 PL0322 5
Mile Road
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