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The interval between stadia marks in most surveying instruments is 10 mrad and gives a stadia interval factor of 100. The distance between the instrument and a stadia rod can be determined simply by multiplying the measurement between the stadia hairs (known as the stadia interval) by 100. The instrument must be level for this method to work ...
Topographer's rods are special purpose rods used in topographical surveys. The rod has the zero mark at mid-height and the graduations increase in both directions away from the mid-height. In use, the rod is adjusted so that the zero point is level with the instrument (or the surveyor's eye if he is using a hand level for low-resolution work).
For example, a typical stadia mark pair are set so that the ratio is 100. If one observes a vertical length on a stadia rod, rule or levelling rod with the telescope and sees that the rod spans 0.500 m between the marks (the stadia interval), then the horizontal distance from the instrument to the rod is: 0.500m x 100 = 50 m.
A topographic survey is typically based upon a systematic observation and published as a map series, made up of two or more map sheets that combine to form the whole map. A topographic map series uses a common specification that includes the range of cartographic symbols employed, as well as a standard geodetic framework that defines the map ...
Stadia marks on a crosshair while viewing a metric levelling rod or staff. The top mark is at 1,500 mm and the lower is at 1,345 mm; the distance between those two marks is 155 mm, yielding a distance to the rod of 15.5 m.
The National Map is a significant contribution to the U.S. National Spatial Data Infrastructure (NSDI) from the Federal Geographic Data Committee (FGDC) and currently is being transformed to better serve the geospatial community by providing high quality, integrated geospatial data and improved products and services including new generation ...
Survey markers, also called survey marks, survey monuments, or geodetic marks, are objects placed to mark key survey points on the Earth's surface. They are used in geodetic and land surveying . A benchmark is a type of survey marker that indicates elevation ( vertical position ).
This 1988 BLM map depicts the principal meridians and baselines used for surveying states (colored) in the Public Land Survey System. The Public Land Survey System (PLSS) is the surveying method developed and used in the United States to plat, or divide, real property for sale and settling.