Diagram displaying the interconnectedness of types of land surveys

Illustration from JW Zollmann, Complete Guide to Geodesy or Practical Geometry, Hall 1744

In this method of earth measurement, the country is covered with a network of triangles (latin: triangula), which collide at their sides and whose corners are formed by high points such as church towers or distinctive hilltops.
At the beginning of a triangulation, a short distance is measured very precisely, from the ends of which a further point is aimed, which then forms the third corner of the first triangle. From each side of this first triangle now more points can be targeted and thus new triangles are formed.
A number of monuments are still reminiscent of the Gaussian land surveying:
the southern meridian sign in the Friedlander Forst, the Gaußturm on the Hohen Hagen and some observation points secured as monuments .

Using an old school level for some construction staking.

Ideally, the total station should meet the following requirements: a) Line of sight ZZ perpen- dicular to tilting axis KK b) Tilting axis KK perpen- dicular to vertical axis VV c) Vertical axis VV strictly vertical d) Vertical-circle reading precisely zero at the zenith If these conditions are not met, the following terms are used to describe the particular errors: a) Line-of-sight error, or colli- mation error c (deviation from the right angle bet- ween the line of sight and the tilting axis) b) Tilting-axis error a (devia- tion from the right angle between the tilting axis and the vertical axis) c) Vertical-axis tilt (angle between plumb line and vertical axis.

In an excavation, a point B is to be set out at a height ∆H = 1.00 metre below street level (Point A). If the points A and B are widely separated, the height difference between them is determined by line levelling with target distances generally between 30 and 50 metres. Pace out the distances between the instrument and the two staffs; they need to be about the same. 1. Set up the instrument at S1. 2. Set up the staff precisely vertically at point B; read off and record the height (backsight R). 3. Set up the staff at the turning point 1 (ground plate or prominent ground point); read off and record the height (foresight V). 4. Set up the instrument at S2 (the staff remains at the turning point 1). 5. Carefully rotate the staff at the turning point 1 so that it faces the instrument. 6. Read off the backsight and continue. The height difference between A and B is equal to the sum of the backsight and the foresight.

In new levels, the com- pensator has been adjusted at room temperature, so that the line of sight is hori- zontal even if the instru- ment is tilted slightly. This situation changes if the temperature fluctuates by more than ten or fifteen degrees, after a long jour- ney, or if the instrument is subjected to strong vibra- tion. It is then advisable to inspect the line of sight, particularly if more than one target distance is being used. 1. In flat terrain, set up two staffs not more than 30 metres apart. 2. Set up the instrument so that it is equidistant from the two staffs (it is enough to pace out the distance) 3. Read off from both staffs and calculate the height difference (illustration above). Staff reading A = 1.549 Staff reading B = 1.404 ∆H = A – B = 0.145 4. Set up the instrument about one metre in front of staff A and take the staff reading (illustration below). Staff reading A = 1.496 5. Calculate the required reading B: Staff reading A = 1.496 - ∆H = 0.145 Required reading B = 1.351 6. Take the staff reading B. If it differs from the required reading by more than 3mm, adjust the line of sight (refer to instruction manual).

The height difference is calculated from the difference between the two staff readings for the points A and B respectively.

1. Set up the level so that the sighting distances to A and B are about the same. 2. Set up the staff at A and read off the backsight R = 1.305. 3. Set up the staff at B and read off the foresight V = 2.520. The difference h from the required height at B is calculated as: h = V – R - ∆H = 2.520 – 1.305 – 1.00 = +0.215m 4. Drive in a post at B and mark the required height (0.215m above ground level). In another frequently-used method, the required staff reading is calculated in advance: V= R - ∆H = 1.305 - (-1.000) = 2.305 The levelling staff is then moved upwards or down- wards until the required value can be read off with the level.

To create e.g. a location plan, the position and height of a point on the object are determined by measuring angles and distances. To do this, the instrument is set up on any prominent point in a local coordinate system. A second prominent point is selected for the purposes of orientation; after this has been targeted the horizontal circle is set to zero (refer to the user manual). If a coordinate system already exists, set up the instrument on a known point within it and line up the horizontal circle with a second known point (refer to the user manual).

Plumbing down from a height point, plumbing up from a ground point, and inspecting a vertical line on a structure, can be carried out exactly in just one tele- scope face, but only if the telescope describes a pre- cisely-vertical plane when it is tilted. To ascertain that this is so, proceed as follows: 1. Target a high point A, then tilt the telescope downwards and mark the ground point B. 2. Transit the telescope, and repeat the procedure in the second face. Mark the point C. The mid-point between the points B and C is the exact plumbing point. The reason why these two points do not coincide can be a tilting-axis error and/or an inclined vertical axis. For work of this type, make sure that the total station has been levelled up pre- cisely, so that the influence of vertical-axis tilt on steep sights is minimized.

This video provides a detailed guide on how to install a standard survey monument in the city of Campbell using city standard drawings of 16 and 18. The video starts by defining survey monuments as physical objects that establish the location of boundary lines in the ground. The city of Campbell uses standard brass marker disks for their survey monuments.

Before starting the installation process, the first step is to verify that the site is free of any underground utility lines using proper equipment. Once verified, the process can begin.

The first hole should be one and a half feet wide and about one and a half feet deep. In the center of this hole, a second hole should be dug out, which should be six inches wide and about one and a half feet deep. The entire depth of the hole should be three feet.

To prepare the location where the brass marker will rest, a six-inch diameter PVC pipe is cut to about two feet in length and placed inside the smaller hole. The pipe must be centered and stable, and a plumb bob is used to accurately center the pipe. On-site, PC concrete is mixed and poured inside the six-inch PVC pipe. The concrete should be poured so that a little mound is formed over the top of the PVC pipe. Once the concrete is poured, the brass marker is placed in the center on top of the concrete, and a plumb bob is used to center the brass marker.

After setting the brass marker in place, the PVC pipe and the standard monument box are stabilized by placing 4 inches of granular material carefully outside of the 6-inch diameter PVC pipe. Then an 8-inch diameter PVC pipe is cut to about 6 inches and placed on top of the granular material, so that the smaller PVC pipe is enclosed inside of it. This serves to protect the brass marker.

The standard monument box is then placed on top of the 8-inch diameter PVC pipe, making sure that the top of the box is perfectly in line with the existing road surface. Adjustments to the PVC pipe shall be made accordingly so that the box is flush with the road. For stabilization, PC concrete is poured in the hole on the outside of the 8-inch PVC pipe and the standard monument box. The top of the concrete should be 2 inches below the road surface pavement. Finally, pavement is poured in the remaining 2 inches of the hole, and the cover is placed on top of the standard monument box.

The video concludes by showing the final result of the survey monument installation.

Rami Tamimi is an American doctorate student at The Ohio State University working towards his Doctor of Philosophy in Geodetic Engineering. With over 8 years of experience in the Land Development Industry, his experience revolves around traditional field surveying, civil design work using AutoCAD Civil 3D, and geospatial technology including LiDAR, SONOR, and Photogrammetric data accusation and processing with the use of Unmanned Aircraft Systems or Drones. He is also a University Professor and creates instructional video content on YouTube.

In this video I take you with me on a simple total station setup and an easy layout of one offset from gridline and we set a few benchmarks.

Structural steel survey and layout are critical processes necessary for building a solid foundation for any construction project. The use of a robotic total station, prism pole, and optical level make it possible to achieve accurate measurements and precise results.

To start, a Trimble RTS 573 robotic total station is used, which requires proper set-up. This involves leveling the tripod, placing the total station on top, and calibrating the device using a Panasonic FCM 1 tablet and Trimble Field Link software. Once calibrated, the instrument is ready for use in storing control, offset layout, setting benchmarks, and plumbing the structure.

During the offset layout process, the robotic total station requires two known points 90 degrees apart from each other. Surveyors use a prism pole, bubble, and prism to obtain angles and perform layout on vertical surfaces. After recording the elevation of the control point, the surveyor focuses on the distance between the offset and reference lines, correcting any discrepancies.

For precise elevation measurements, the prism center's height must be within 1/8th of an inch. The surveyor inputs the rod height and measures the angle, producing an offset measurement that is accurately read by everyone, ensuring error-free results. The surveyor marks the position, checks the elevation, and cleans the marked surface for later adjustments.

Finally, a total station can also be used to measure the elevations of different points in a building. This process involves cleaning the area and holding the device steady to achieve accurate results. The device produces clear and precise points, with the option of using the control to regain lost locks.

To summarize, structural steel survey and layout require precise measurements and attention to detail. This is achieved using a robotic total station, prism pole, and optical level that make it possible to obtain accurate measurements and precise results necessary in creating a solid foundation for any building.

 

I have shared an excel spreadsheet for Traverse Corrections and Traverse Calculations by Compass Rule or Bowditch Rule. Also I have described about Traversing: what are the types of Traverse (closed traverse, Open Traverse), Traverse calculations and adjustment of closing errors, traverse precision, latitude and departure, Bowditch Rule/Compass Rule, Transit Rule etc. I have prepared an excel spreadsheet for Traverse Corrections and Traverse Calculations, you can download the file from the above link. Surveying Traverse: How to Close a Traverse: Traverse adjustment If it relates to you then Like & Share this video and Subscribe our channel to get free updates!

In this video I show you how to use Trimble Access to Survey with one base and two rovers

Surveying equipment plays a key role in collecting accurate and reliable data for various purposes. Among the commonly used surveying instruments are Total Station and GNSS receivers. The two devices differ in their setup and operational processes, as well as in their accuracy and limitations.

Setting up a Total Station involves occupying a known coordinate point, laying out the tripod, and pointing towards a surveying prism to obtain measurements. In contrast, setting up a GNSS receiver is faster and involves attaching the receiver to a pole and connecting it to a controller. However, GNSS receivers struggle with obstructions such as tree and canopy coverage, while the Total Station is more accurate but may have errors due to relative distance measurements.

When surveying a residential home, using a Total Station around the house may be time-consuming, while using a GNSS receiver provides more control and mobility. In the summer when there is a lot of leaf coverage on trees, using a GNSS receiver becomes difficult due to tree canopies creating a forest ceiling. However, with the Leica gs18i GNSS receiver, image capture aids in data collection, providing centimeter-level accuracy in areas where the GNSS receiver is obstructed.

Comparing the accuracy of the devices, Total Station is more accurate with a difference of about one to one and a half millimeters, while GNSS receivers provide horizontal discrepancies of seven hundredths of a foot. Total Station uses a local coordinate system, while GNSS receivers provide geodetic positions. In assessing the accuracy of the GNSS receiver, point number one and point number two need to be observed and inversed between.

In conclusion, choosing the right surveying instrument depends on the specific requirements of the job at hand. Total Station may be more accurate but require more time and setup, while GNSS receivers provide more flexibility but struggle with obstructions. It is important to carefully consider all factors and limitations before selecting the appropriate tool for the task.

Basics of setting up and operating a total station: leveling, station orientation, backsighting, and shooting points. For the course Archaeological Excavation, Vanderbilt University.

Here are 9 best practices that will help you station your total station on accurate control points on your jobsite.

Best Practices for Control Points and Tool Setup in the Field

When it comes to surveying and layout work, accuracy is paramount. Control points play a crucial role in ensuring accurate measurements and layout. In this article, we will discuss the best practices for control points and tool setup in the field, highlighting the key considerations that can help improve accuracy and efficiency.

Quick Reminders before Working: Before delving into the best practices, let's quickly recap some essential points to keep in mind when starting a new job. These reminders will set you up for success:

1. Use Accurate Control Points: It is imperative to use precise and reliable control points. Accuracy in control points is fundamental to achieving accurate layout results.

2. Allocate Sufficient Time: Take the time needed to establish your control points correctly. Budget at least half a day on your first workday for analyzing, troubleshooting, and verifying the accuracy of control points.

3. Collaborate with the General Contractor (GC): Share your findings regarding the control points with the GC. This communication ensures that the information can be synchronized and utilized by all trades on the job site, enhancing accuracy and boosting your credibility.

4. Work with the Surveyor: Whenever possible, collaborate closely with the surveyor from day one. Observe how they establish their control points, inspect their work, and gain insights into their placement strategies on the job site.

Best Practices for Control Points and Tool Setup:

1. Center Your Tool and Have Clean Angles: Position your total station in the center of your layout area to maximize its reach and minimize the need for frequent repositioning. Additionally, ensure that the angles between control points and the total station are clean and preferably around 90 degrees. Avoid extreme angles to minimize errors and maintain accuracy.

2. Have Access to 4-5 Control Points If Possible: Aim to have access to at least three control points, preferably four to five. This provides flexibility in stationing your tool at various locations on the job site. It also allows you to eliminate control points that might have shifted or become inaccurate while maintaining a sufficient number of reference points for accurate stationing.

3. Ensure Control Points Encompass Your Layout Area: Make sure your control points are strategically placed to encompass your entire layout area. This ensures that all your layout points fall within the control points, guaranteeing accuracy and consistency throughout the job.

4. Identify Secure (Unmovable) and Stable Control Points: Identify control points that are secure and unlikely to move. Avoid using control points that are susceptible to displacement or disturbance. Secure control points provide a reliable reference for accurate stationing and layout.

Implementing best practices for control points and tool setup in the field is vital for achieving accurate and reliable surveying and layout results. By following these guidelines, surveyors can enhance accuracy, minimize errors, and improve efficiency on job sites. Remember to use accurate control points, allocate sufficient time for analysis and troubleshooting, collaborate with the GC and surveyor, and strategically position your total station for optimal results. These practices will contribute to successful and precise surveying and layout work.

This is a detailed video that describes what the total station does to "best fit" your control points to what the digital plan is asking for. If these are accurate, you will be able to have a very accurate layout. Knowing how the tool adjusts inaccurate control points should help you find and resolve control point errors on your jobsite. You will notice one typo: I accidentally change the 49' 6" measurement to 45' 6". Please note that it should be reading 49' 6" the whole time. Thanks again for watching!

Foreign equipped with a leveling rod and an instrument we can measure elevation differences. In this video, we'll explore the basic field processes involved in measuring those differences and then computing elevations. I'm Todd Horton for the Illinois professional land surveyors Association.

Using an optical level, we create a horizontal line of sight where our line of sight intersects the leveling rod. We take rod readings, and with these readings, we can compute elevation differences. With practice, most instrument operators can confidently read the rod when it is 250 feet away. Thus, if I need to find the rise between two locations 500 feet apart, I simply set up halfway between the points and take two readings.

But what if I can't see between those points? For instance, in this scenario, the elevation difference is greater than the height of my tripod. Or what if the locations are 5,000 feet apart? Well, to overcome these obstacles, we perform a level circuit. We perform a level circuit by measuring a series of elevation differences end to end.

In the first video, we illustrated the concept with the carpenter level. But now we do the same process on a grander scale with an optical level. To find an unknown elevation shown here on the right, we must first start from an elevation that is known, shown here on the left.

An elevation is a vertical distance above or below a reference surface. We commonly use mean sea level as a reference surface. For instance, the summit of Mount Everest is 29,029 feet above mean sea level, and the lowest point in the United States is Death Valley at 282 feet below sea level. By measuring vast networks of level circuits across the continent, surveyors have established heights above sea level at stable permanent benchmarks. Benchmarks come in many forms and are attached to everyday objects like bridges and fire hydrants.

Let's walk through a typical level circuit we call Benchmark leveling. You may hear this process called differential leveling or control leveling as well. Here, our survey site is half a mile from the nearest benchmark across a shallow valley. We need to determine the elevation of a newly constructed benchmark on the site. Because of the terrain and the distance involved, we'll have to set up the instrument multiple times to measure a series of elevation differences.

First, we'll set up our instrument where we can see the rod sitting atop the known benchmark. Our first rod reading is 4.69 feet. Since this reading is taken on a point of known elevation, we call it a backside (BS). With this first backside reading and the known elevation of the benchmark (842.17 feet in our case), we can say the instrument line of sight is 4.69 feet above the elevation of 842.17. Thus, the HI (height of the instrument) is 842.17 feet plus 4.69 feet, which equals 848.86 feet.

When the backside reading is complete, the rod person can move beyond the instrument operator toward the survey site. At a convenient location where the instrument is visible, the rod person will create a turning point. A turning point is a temporary intermediate point in a level circuit that we use like a benchmark. Each turning point must be stable and have a distinct peak or high point on which the rod will rest. Here, the rod person is using a cold chisel driven firmly into the ground. When it is stable, its top can have only one elevation. This concrete curb has high spots that make good turning points, and this sidewalk corner will work too.

With the rod person holding the leveling rod at the top turning point (labeled TP1), the instrument operator can make another rod reading called a foresight (FS). A foresight is a rod reading taken on a point of unknown elevation. Since we don't yet know the elevation of Turning Point 1, the first reading there is a foresight. Our foresight reading at Turning Point 1 is 6.08 feet.

Since we know the HI is 848.86 feet and the instrument line of sight is 6.08 feet above Turning Point 1, we can now compute the elevation there. We'll subtract the foresight reading from the HI: 848.86 feet minus 6.08 feet equals 840.78 feet. Now we know the elevation of Turning Point 1.

Next, in order to extend our circuit toward the new benchmark, the rod person will stay put while the instrument operator moves beyond Turning Point 1. At a new location where the rod is clearly visible, the instrument operator will set up the instrument and take a new reading on the rod at Turning Point 1.

Now, an important question arises: Will this reading be a backside or a foresight? A backside reading is a reading on a point of known elevation, while a foresight is a reading on a point of unknown elevation. So, which is it in this case?

Well, Turning Point 1 has a known elevation based on our first instrument setup. So, with a backside reading of 2.95 feet, the instrument has a new HI. The line of sight is 2.95 feet above the Turning Point 1 elevation of 840.78 feet, giving an HI of 843.73 feet. Now, the rod person can leave Turning Point 1.

Turning points are for short-term temporary use. After reading both a foresight and a backside on the cold chisel turning point, the rod person can remove it and move beyond the instrument to set a turning point at a convenient location. With a foresight of 7.17 feet, the elevation of Turning Point 2 will be 836.56 feet.

The process repeats at each new instrument setup. There will be a new backside reading and a new HI at each new instrument setup. The operator will take two readings: a backside and a foresight at each turning point. The rod person will hold the rod at the 0.42 readings, first a foresight and second a backside. In the field, the rod person and the instrument operator move separately, taking turns and moving forward in a leapfrog pattern.

With the final foresight, there are finally enough measurements with which to compute the elevation of the new benchmark. The process is fairly simple, repetitive, and efficient.

So far, you've seen the core concepts. In the next video, I'll show you how to prevent mistakes, how to record your readings, and how to compute with confidence.

I'm Todd Horton for the Illinois Professional Land Surveyors Association.

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Land surveying is the process of measuring and mapping the physical features of a piece of land. One important aspect of land surveying is the process of leveling. Leveling is the process of determining the relative heights or elevations of points on the ground.

To get started with leveling in land surveying, you will need the following equipment:

1. Leveling rod - a long, straight rod with marks on it for measuring height.

2. Level - a tool used to determine whether a surface is level or not.

3. Tripod - a three-legged stand used to support the level.

4. Plumb-bob - a weight attached to a string used to determine vertical alignment.

5. Measuring tape - a long, flexible tape used to measure distances.

Here are the basic steps to follow when leveling in land surveying:

1. Set up the tripod on firm, level ground. Make sure it is stable and secure.

2. Attach the level to the tripod, making sure it is properly leveled.

3. Place the leveling rod at the point you want to measure, holding it vertical and steady.

4. Look through the level to determine the height of the rod. Record the measurement.

5. Move the leveling rod to the next point you want to measure and repeat the process.

6. Continue measuring the heights of different points on the land until you have the data you need.

7. Use the data to create a contour map or elevation profile, which shows the relative elevations of different points on the land.

It's important to note that there are different types of leveling techniques and equipment, depending on the complexity and precision of the surveying project. This is just a basic overview to get you started. If you need to conduct more complex surveys, it's recommended to consult with a licensed land surveyor.

Automatic Data Extraction of Survey Departmental Hardcopy Documents

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