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tape-and-compass-survey-design He also showed how to resectionor calculate, the position of a point inside a triangle using the angles cast between the vertices at the unknown point. White Portland cement, as the name indicates, is a kind of cement with white color. The directions shown are for 66 degrees, degrees, and degrees, all using a degree circle for direction. Vinny says:. If no bearing is known or direct angle measurement is wanted, the instrument can be set to zero tape and compass survey design the initial sight. Follow Us on Facebook! The same three directions as stated in the previous example of 66 degrees, degrees and degrees can be expressed in their bearing equivalents of North 66 degrees East, S 15 degrees east, and North 30 degrees west, as shown tape and compass survey design the diagram below.

Likewise a bearing of S 15 degrees east means the direction is 15 degrees to the east of due south. The same three directions as stated in the previous example of 66 degrees, degrees and degrees can be expressed in their bearing equivalents of North 66 degrees East, S 15 degrees east, and North 30 degrees west, as shown in the diagram below.

As you can see from the diagram, the same angles we expressed in degrees are now expressed in bearings. You may be wondering why anyone would use a system of bearings instead of degrees. This is somewhat anachronistic.

Surveyors of old used this system because it was easier to compute areas and closure more on this subject later using the bearings rather than degrees. While almost all calculations done today are done with computer programs, we are left with the customs of old. In looking at plats you rarely find the bearings expressed only in degrees. Usually you will find the bearing expressed as degrees, minutes, and seconds. Minutes and seconds are divisions of a degree with one degree equalling 60 minutes and one minute equalling 60 seconds.

This derives from early nautical derivations and again is somewhat anachronistic. Bearings will always begin with either S or N, followed by the degrees minutes and seconds, followed by E or W.

Now lets put it together. Below is a representation of a property with 5 points, each seperated by a distance and a direction given in bearings. Think of each crosshair as a relative direction guide with North being towards the top of each crosshair. That is to say that the direction of travel and distance from one point to the other and back to the beginning is in a clockwise direction.

The text is also oriented in the direction of travel. Plats do not have to follow this convention, but most do. It is easy to see if this is correct by looking at the drawing. The direction of travel from point 1 to point 2 is Northwest and this coincides with the call since the first and last letters of the direction are N and W respectively. As a note of interest, if you encounter a call that is in the wrong direction, the direction of travel can be easily reversed by simply exchanging both directions on the call.

Remember to change both directions. This concludes Part II of our quick guide to plats of survey. Stay tuned for the final part of this blog which will explain errors of closure, calculation of acreage, curves, and special considerations. You can usually find a copy of your plat in the office of the clerk of superior court of your county if it has been recorded. Thank you so much for this helpful article! Should be required reading for real property courses in law school.

And you can look our website about powerful love spells. Safest husband toasts, or toasts. Your writing style is witty, keep up the good work! I inherited some land located in south Georgia. I am planning to sell it in the near future. Two other heirs sold parcels some time ago. Will I need to have a survey done or can I use one that should be in the public record?

I know the state of GA says a final plat has to be registered with the Clerk. How do I find the coordinates using this system? If I know the coordinates of one point, can I calculate the others? Thanks to the guy who posted this info and it keeping it online. Basically, taking bearings azimuths off a reference stake on the plat and using a ft tape measure to position the stakes. Perfect info — thanks again! Thanks for this post.

Still relevant and gave me the tools needed to begin to understand a complex survey today. Question: On a boundary survey for a residential lot, the surveyor gives a measured bearing then he gives a Plat bearing in parentheses, which is correct?

My survey shows the direction and the number of feet between each point. There is a elevation change of 75 feet between the 2 points at a marked distance of feet. Is that feet measured parallel along the ground or horizontally?

Thank you. I appreciate these information from. I am trying to find them. Great beat! I wish to apprentice at the same time as you amend your web site, how could i subscribe for a weblog web site? Your email address will not be published. Connect with Facebook. Georgia Land Sales Blog. Skip to content. What are those strange birds? Guinea Fowl! He is a licensed real estate broker and has over 37 years experience in selling land, farms, acreage, commercial and investment properties.

This entry was posted in Uncategorized. Bookmark the permalink. August 4, at pm. Bryan Borman says:. January 17, at am. March 25, at pm. Tice Brashear says:. May 5, at am. Claudette says:. May 17, at pm.

Steve says:. The vertical circle measures the angle that the telescope makes against the vertical, known as the zenith angle. The horizontal circle uses an upper and lower plate. When beginning the survey, the surveyor points the instrument in a known direction bearing , and clamps the lower plate in place. The instrument can then rotate to measure the bearing to other objects.

If no bearing is known or direct angle measurement is wanted, the instrument can be set to zero during the initial sight. It will then read the angle between the initial object, the theodolite itself, and the item that the telescope aligns with.

The gyrotheodolite is a form of theodolite that uses a gyroscope to orient itself in the absence of reference marks. It is used in underground applications. The total station is a development of the theodolite with an electronic distance measurement device EDM. A total station can be used for leveling when set to the horizontal plane.

Since their introduction, total stations have shifted from optical-mechanical to fully electronic devices. Modern top-of-the-line total stations no longer need a reflector or prism to return the light pulses used for distance measurements. They are fully robotic, and can even e-mail point data to a remote computer and connect to satellite positioning systems , such as Global Positioning System.

Real Time Kinematic GPS systems have increased the speed of surveying, but they are still only horizontally accurate to about 20 mm and vertically to 30—40 mm. Static GPS uses two receivers placed in position for a considerable length of time. The long span of time lets the receiver compare measurements as the satellites orbit. The changes as the satellites orbit also provide the measurement network with well conditioned geometry.

This produces an accurate baseline that can be over 20 km long. RTK surveying uses one static antenna and one roving antenna. The static antenna tracks changes in the satellite positions and atmospheric conditions. The surveyor uses the roving antenna to measure the points needed for the survey. The two antennas use a radio link that allows the static antenna to send corrections to the roving antenna.

The roving antenna then applies those corrections to the GPS signals it is receiving to calculate its own position. RTK surveying covers smaller distances than static methods. This is because divergent conditions further away from the base reduce accuracy.

Surveying instruments have characteristics that make them suitable for certain uses. Theodolites and levels are often used by constructors rather than surveyors in first world countries. The constructor can perform simple survey tasks using a relatively cheap instrument. Total stations are workhorses for many professional surveyors because they are versatile and reliable in all conditions.

The productivity improvements from a GPS on large scale surveys makes them popular for major infrastructure or data gathering projects. One-person robotic-guided total stations allow surveyors to measure without extra workers to aim the telescope or record data.

A fast but expensive way to measure large areas is with a helicopter, using a GPS to record the location of the helicopter and a laser scanner to measure the ground. To increase precision, surveyors place beacons on the ground about 20 km 12 mi apart. This method reaches precisions between 5—40 cm depending on flight height. Surveyors use ancillary equipment such as tripods and instrument stands; staves and beacons used for sighting purposes; PPE Tape And Compass Survey Technology ; vegetation clearing equipment; digging implements for finding survey markers buried over time; hammers for placements of markers in various surfaces and structures; and portable radios for communication over long lines of sight.

Land surveyors, construction professionals, and civil engineers using total station , GPS , 3D scanners, and other collector data use Land Surveying Software to increase efficiency, accuracy, and productivity. Land Surveying Software is a staple of contemporary land surveying. Typically, much if not all of the drafting and some of the designing for plans and plats of the surveyed property is done by the surveyor, and nearly everyone working in the area of drafting today utilizes CAD software and hardware both on PC, and more and more in newer generation data collectors in the field as well.

Surveyors determine the position of objects by measuring angles and distances. The factors that can affect the accuracy of their observations are also measured. They then use this data to create vectors, bearings, coordinates, elevations, areas, volumes, plans and maps. Measurements are often split into horizontal and vertical components to simplify calculation.

GPS and astronomic measurements also need measurement of a time component. These included chains with links of a known length such as a Gunter's chain , or measuring tapes made of steel or invar. To measure horizontal distances, these chains or tapes were pulled taut to reduce sagging and slack. The distance had to be adjusted for heat expansion. Attempts to hold the measuring instrument level would also be made. When measuring up a slope, the surveyor might have to "break" break chain the measurement- use an increment less than the total length of the chain.

Perambulators , or measuring wheels, were used to measure longer distances but not to a high level of accuracy. Tacheometry is the science of measuring distances by measuring the angle between two ends of an object with a known size.

It was sometimes used before to the invention of EDM where rough ground made chain measurement impractical. Historically, horizontal angles were measured by using a compass to provide a magnetic bearing or azimuth. Later, more precise scribed discs improved angular resolution. Mounting telescopes with reticles atop the disc allowed more precise sighting see theodolite.

Levels and calibrated circles allowed measurement of vertical angles. Verniers allowed measurement to a fraction of a degree, such as with a turn-of-the-century transit. The plane table provided a graphical method of recording and measuring angles, which reduced the amount of mathematics required.

In Francis Ronalds invented a reflecting instrument for recording angles graphically by modifying the octant. By observing the bearing from every vertex in a figure, a surveyor can measure around the figure. This is called a close. If the first and last bearings are different, this shows the error in the survey, called the angular misclose. The surveyor can use this information to prove that the work meets the expected standards.

The simplest method for measuring height is with an altimeter using air pressure to find height. When more precise measurements are needed, means like precise levels also known as differential leveling are used. When precise leveling, a series of measurements between two points are taken using an instrument and a measuring rod. Differences in height between the measurements are added and subtracted in a series to get the net difference in elevation between the two endpoints.

Usually GPS is somewhat less accurate than traditional precise leveling, but may be similar over long distances. When using an optical level, the endpoint may be out of the effective range of the instrument. There may be obstructions or large changes of elevation between the endpoints.

In these situations, extra setups are needed. Turning is a term used when referring to moving the level to take an elevation shot from a different location.

To "turn" the level, one must first take a reading and record the elevation of the point the rod is located on. While the rod is being kept in exactly the same location, the level is moved to a new location where the rod is still visible. A reading is taken from the new location of the level and the height difference is used to find the new elevation of the level gun, which is why this method is referred to as differential levelling.

This is repeated until the series of measurements is completed. The level must be horizontal to get a valid measurement. Because of this, if the horizontal crosshair of the instrument is lower than the base of the rod, the surveyor will not be able to sight the rod and get a reading.

The rod can usually be raised up to 25 feet 7. The primary way of determining one's position on the earth's surface when no known positions are nearby is by astronomic observations. Observations to the sun, moon and stars could all be made using navigational techniques.

Once the instrument's position and bearing to a star is determined, the bearing can be transferred to a reference point on the earth. The point can then be used as a base for further observations. Survey-accurate astronomic positions were difficult to observe and calculate and so tended to be a base off which many other measurements were made.

Since the advent of the GPS system, astronomic observations are rare as GPS allows adequate positions to be determined over most of the surface of the earth. Few survey positions are derived from first principles. Instead, most surveys points are measured relative to previous measured points. This forms a reference or control network where each point can be used by a surveyor to determine their own position when beginning a new survey.

Survey points are usually marked on the earth's surface by objects ranging from small nails Tape And Compass Survey Website driven into the ground to large beacons that can be seen from long distances.

The surveyors can set up their instruments on this position and measure to nearby objects. Sometimes a tall, distinctive feature such as a steeple or radio aerial has its position calculated as a reference point that angles can be measured against. It can determine distances, elevations and directions between distant objects. Since the early days of surveying, this was the primary Tape And Compass Survey Job method of determining accurate positions of objects for topographic maps of large areas.

A surveyor first needs to know the horizontal distance between two of the objects, known as the baseline. Then the heights, distances and angular position of other objects can be derived, as long as they are visible from one of the original objects. High-accuracy transits or theodolites were used, and angle measurements repeated for increased accuracy. See also Triangulation in three dimensions. Offsetting is an alternate method of determining position of objects, and was often used to measure imprecise features such as riverbanks.

The surveyor would mark and measure two known positions on the ground roughly parallel to the feature, and mark out a baseline between them. At regular intervals, a distance was measured at right angles from the first line to the feature. The measurements could then be plotted on a plan or map, and the points at the ends of the offset lines could be joined to show the feature.

Traversing is a common method of surveying smaller areas. The surveyor starts from an old reference mark or known position and places a network of reference marks covering the survey area. They then measure bearings and distances between the reference marks, and to the target features. Most traverses form a loop pattern or link between two prior reference marks so the surveyor can check their measurements.

Many surveys do not calculate positions on the surface of the earth, but instead measure the relative positions of objects. However, often the surveyed items need to be compared to outside data, such as boundary lines or previous survey's objects.

The oldest way of describing a position is via latitude and longitude, and often a height above sea level. As the surveying profession grew it created Cartesian coordinate systems to simplify the mathematics for surveys over small parts of the earth.

The simplest coordinate systems assume that the earth is flat and measure from an arbitrary point, known as a 'datum' singular form of data. The coordinate system allows easy calculation of the distances and direction between objects over small areas. Large areas distort due to the earth's curvature. North is often defined as true north at the datum. For larger regions, it is necessary to model the shape of the earth using an ellipsoid or a geoid. Many countries have created coordinate-grids customized to lessen error in their area of the earth.

A basic tenet of surveying is that no measurement is perfect, and that there will always be a small amount of error. Surveyors avoid these errors by calibrating their equipment, using consistent methods, and by good design of their reference network. Repeated measurements can be averaged and any outlier measurements discarded. Independent checks like measuring a point from two or more locations or using two different methods are used, and errors can be detected by comparing the results of two or more measurements, thus utilizing redundancy.

Once the surveyor has calculated the level of the errors in his or her work, it is adjusted. This is the process of distributing the error between all measurements. Each observation is weighted according to how much of the total error it is likely to have caused and part of that error is allocated to it in a proportional way.

The most common methods of adjustment are the Bowditch method, also known as the compass rule, and the principle of least squares method. The surveyor must be able to distinguish between accuracy and precision. In the United States, surveyors and civil engineers use units of feet wherein a survey foot breaks down into 10ths and ths. Many deed descriptions containing distances are often expressed using these units Calculation and mapping tolerances are much smaller wherein achieving near-perfect closures are desired.

Though tolerances will vary from project to project, in the field and day to day usage beyond a th of a foot is often impractical. Local organisations or regulatory bodies class specializations of surveying in different ways. Broad groups are:. Based on the considerations and true shape of the earth, surveying is broadly classified into two types. Plane surveying assumes the earth is flat. Curvature and spheroidal shape of the earth is neglected. In this type of surveying all triangles formed by joining survey lines are considered as plane triangles.

It is employed for small survey works where errors due to the earth's shape are too small to matter. In geodetic surveying the curvature of the earth is taken into account while calculating reduced levels, angles, bearings and distances. This type of surveying is usually employed for large survey works. Survey works up to square miles square kilometers are treated as plane and beyond that are treated as geodetic.

The basic principles of surveying have changed little over the ages, but the tools used by surveyors have evolved. Engineering, especially civil engineering, often needs surveyors.

Surveyors help determine the placement of roads, railways, reservoirs, dams, pipelines , retaining walls , bridges, and buildings. They establish the boundaries of legal descriptions and political divisions.

They also provide advice and data for geographical information systems GIS that record land features and boundaries. Surveyors must have a thorough knowledge of algebra , basic calculus , geometry , and trigonometry.

They must also know the laws that deal with surveys, real property , and contracts. Licensing requirements vary with jurisdiction, and are commonly consistent within national borders. Prospective surveyors usually have to receive a degree in surveying, followed by a detailed examination of their knowledge of surveying law and principles specific to the region they wish to practice in, and undergo a period of on-the-job training or portfolio building before they are awarded a license to practise.

Licensed surveyors usually receive a post nominal , which varies depending on where they qualified. The system has replaced older apprenticeship systems. A licensed land surveyor is generally required to sign and seal all plans.

The state dictates the format, showing their name and registration number. In many jurisdictions, surveyors must mark their registration number on survey monuments when setting boundary corners. Monuments take the form of capped iron rods, concrete monuments, or nails with washers. Most countries' governments regulate at least some forms of surveying.

Their survey agencies establish regulations and standards. Standards control accuracy, surveying credentials, monumentation of boundaries and maintenance of geodetic networks. Cadastral surveys tend to be the most regulated because of the permanence of the work.

Lot boundaries established by cadastral surveys may stand for hundreds of years without modification.

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