Benchmarking Meaning Definition Process Examples and Analysis. Benchmarking, also known as benchmark hunting, is a hobby pastime wherein members discover benchmarks (also known as survey markers or geodetic manipulate points). Technically, the term “benchmark” is used only to refer to survey markers that explain a sure elevation, however, hobbyists regularly use the term benchmarks to encompass triangulation stations or different reference marks. They normally then log theirs unearths online.
Many survey markers within the U.S. have been set over 100 years ago. there was additionally a surge in creating those marks within the U.S. from approximately 1930 to 1955, together with the enlargement of map-making sports throughout the USA. Inside the U.S. a number of those marks (triangulation stations and GPS points, loosely also called “benchmarks”) have unique “adjusted” coordinates (range and longitude).
The “ADJUSTED” coordinates are particular to sub-centimeter accuracy, at the same time as others, commonly proper elevation Bench Marks, have handiest coordinates scaled from a map. “SCALED” coordinates were examined from a topographic map, in place of being surveyed. Many are accurate to a hundred feet however some areas a good deal as three,000 or 4,000 feet distant from the mark to which they refer, rendering a hand-held GPS unit of little use in locating them. maximum marks have clean “to-reach” descriptions, however, a few lacks complete descriptions, or modifications in the surrounding buildings, roads, or terrain over decades make the descriptions out of date. Marks may additionally have been removed by means of production or buried.
Resources of records on U.S. marks
Inside the U.S., about 740,000 “benchmarks” with the most unique elevations or coordinates (however best a small fraction of the present survey marks) are indexed in a database maintained through the country-wide Geodetic Survey (NGS) and available 8db290b6e1544acaffefb5f58daa9d83. most of the people of marks set via the U.S. Geological Survey (USGS), the wooded area service, the Corps of Engineers, or cities, and states, and nearby authorities. Cadastral (land survey) marks are normally no longer measured for the geodetic information base. The database utilized by Geocaching.com, the hobbyist website for U.S. benchmark hunters, is only a “photo” of the marks that the NGS had documented by using the yr 2000, and has not been up to date since then.
Each NGS-indexed mark has an everlasting identifier (PID), a six-man or woman code that can be used to call up information approximately that mark. the use of a form for a web query like this, the PID for the mark may be entered and an information sheet for the mark viewed. A statistics sheet received thru this kind of query seems like this. there’s also an internet site that uses Google Maps to expose the locations (and PIDs) of marks in every character kingdom of the U.S. specialized hobbyist websites (like Geocaching.com) FAQ and its Benchmark looking discussion board can offer extra statistics.
Further to the survey information sheet for a mark being hunted, many hunters convey alongside a virtual digicam to take close-up and area photographs of the survey mark (a disk, a move cut in a rock, an old copper bolt, and many others.). those images, in addition to a modern-day description of the mark by the person that unearths (“recovers”) the region of the mark, can then be uploaded to a website as proof of locate. Surveyors use the term “improving” as a synonym for “locating” a mark. this doesn’t suggest that the observed mark must be disturbed in any way. on the opposite—traumatic a survey mark in even a small manner frequently destroys its usefulness to surveyors and others. within the U.S., benchmark hunters frequently report one-of-a-kind reviews on marks they find. One, much less formal, is made to the website at Geocaching.com. the opposite more formal type is made with the aid of extra experienced and cautious hunters to the NGS database itself and describes the mark’s observed/not discovered reputation, present-day circumstance, and updated online to attain it so that others (especially surveyors) can more without difficulty re-discover the mark.
Benchmark hunters additionally often convey a compass (to comply with directions on line gleaned from the information sheet), a probe (like an extended-bladed screwdriver) to look for buried marks, a trowel (or a small shovel) to discover buried marks, a whisk broom (to clean away debris), and one or extra tape measures of numerous lengths, used in taping out referenced distances found at the statistics sheets.
hand-held GPS receivers are regularly used to get within a few yards in all likelihood errors of a mark that has adjusted coordinates. metal detectors are beneficial for finding marks that have to grow to be deeply buried over the years. Use of numerous of the tools in aggregate is every so often required, but many marks are set on the floor of sidewalks, homes, partitions, boulders, or monuments and can regularly be determined without special tools.
Description of markers
Survey markers vary notably from one USA to another another. in the united states they may be normally bronze discs approximately three.5 inches in diameter. a typical disk is barely inset into the pinnacle of a concrete pillar set vertically with its floor flush with the ground or projecting barely. Others are metal rods pushed into the floor and probably surrounded by means of a capped metal or plastic pipe that may be engraved and stamped like disks. Disks can also be set in rock ledges or boulders, and inside the concrete of a huge shape inclusive of a building, bridge abutment, the bottom of a tower. in the united kingdom, the mark is normally carved right into a wall, or on a metallic plate set into a wall.
Inside the U.S., a survey disk is commonly engraved with the call of the company that placed it. The call of the mark (or the “station” it locates) is commonly stamped into its floor, along with the date on which it becomes set (or re-set, considering markers that have been destroyed can be replaced). Disks marked with a triangle are referred to as “triangulation station disks”, on the grounds that they mark the location of the number one factor used for triangulation (or map-making). Disks marked with an arrow are referred to as reference marks (RMs), considering they point (or “refer”) to the fundamental station that may be positioned many feet away. A triangulation station often had or 3 reference marks. Reference marks had been set to allow the number one station to be re-established (or re-set) if wanted.
Every now and then a survey mark is made plenty easier to discover with the aid of the presence close by of a witness publish, a stake (or a small signal) pushed into the ground and used to draw attention to (and to warn towards traumatic) the mark.
Care must be taken to assure that a determined disk is the only one described on the information sheet so that you can keep away from fake reports. A reference mark can be mistakenly suggested as the station mark. A disk set in 1945 can be confused with a similarly named disk that became set in 1946 by a special corporation, and so forth. A RESET elevation benchmark ought to no longer be stated as unique. finding out those differences and reporting them correctly is a critical part of the interest.
within the U.S., markers are often located on the summits of mountains, along ridge online, or on bare rock ledges with commanding views, due to the fact, such websites provided excellent vantage factors for triangulation online to distant factors.
U.S. elevation benchmarks had been often located along rail on-line or roads that supplied desirable sight online for leveling. All active and some abandoned railroad rights of manner are private assets, actively patrolled through railroad police.
A commonplace location is the pinnacle level of the abutment of a toll road bridge or its wing walls.
As a part of triangulation networks, intersection stations had been sighted. they are typically tall, outstanding, and properly defined points like a smokestack, the height of a water tower, or a church spire. but, many of those items have been altered or changed by way of comparable close by structures and now not mark the unique place, so cautious identity is needed.
U.S. benchmarks have been usually positioned on public homes, along with courthouses, publish places of work, metropolis halls, and older colleges.
Benchmarks are frequently placed on private belongings, or get the right of entry to them can most effectively be achieved through crossing privately owned land, so permission is needed to getting admission.
In the UK
An Ordnance Survey flush bracket inside the united kingdom
UK benchmarks have a tendency to be at the corners of pubs, church buildings, and other public buildings, as well as farm buildings, railway bridges, and private houses particularly those close to an avenue junction. however, any construction may be used, in addition to herbal features along with a rock outcrop.
In the UK, trig pointing is a leisure pastime just like benchmarking. searching for trig factors is greater popular than looking at benchmarks in the united kingdom, but there is a vast overlap in participation. “Trig factors” is the commonplace call for “triangulation pillars”. these are concrete pillars, approximately four feet tall, which have been used by the Ordnance Survey so one can decide the exact shape of the united states of America in a project referred to as the triangulation of top-notch Britain, which changed into finished from 1936 to 1962. they’re generally placed on the highest little bit of ground inside the location, so that there may be an immediate online of sight from one to the following. By placing a theodolite at the top of the pillar, accurate bearings to close by trig factors can be taken. This method is referred to as triangulation.
There are 6550 such pillars listed inside the T:UK database. even as most of them have fallen into disuse, about 184 of them are presently used within the Passive Station community. these are maintained in order that they may be used as correctly located anchor factors for differential GPS comparisons, and are re-surveyed every five years to calibrate for any geological actions of the ground.
Read more: https://en.wikipedia.org/wiki/Benchmarking_(hobby)