1.1 Establishing large area Geodetic control Network
A geodetic control network (also geodetic network, reference network, control point network, or control network) is a network, often of triangles, which are measured exactly by techniques of terrestrial surveying or by satellite geodesy.
A geodetic control network consists of stable, identifiable points with published datum values derived from observations that tie the points together.
Classically, a control is divided into horizontal (X-Y) and vertical (Z) controls (components of the control), however with the advent of satellite navigation systems, GPS in particular, this division is becoming obsolete.
The higher-order (high precision, usually millimeter-to-decimeter on a scale of continents) control points are normally defined in both space and time using global or space techniques, and are used for “lower-order” points to be tied into. The lower-order control points are normally used for engineering, construction and navigation. The scientific discipline that deals with the establishing of coordinates of points in a high-order control network is called geodesy, and the technical discipline that does the same for points in a low-order control network is called surveying.
1.2 Establishing geodetic control for Construction
Conventional surveys are those performed using traditional precise surveying techniques and instruments–i.e., theodolites, total stations, and levels. Conventional control surveys can be used to economically and accurately establish or densify project control in a timely fashion. Quality control statistics and redundant measurements in networks established by these methods help to ensure reliable results. However, conventional survey methods do have the requirement for intervisibility between adjacent stations.
GPS satellite surveying techniques can often be used to establish or densify project control more efficiently (and accurately) than conventional control urveying techniques– especially over large projects. As with conventional methods, quality control statistics and redundant measurements in GPS etworks help to ensure eliable results. Field operations to perform a GPS survey are relatively easy and can generally be performed by one person per receiver, with two or more receivers required to transfer control. GPS does not require intervisibility between adjacent stations.
The most important addition to the geodetic surveying community was the introduction of the Navstar Global Positioning System (GPS), allowing the surveying industry to establish affordable, high-accuracy geodetic control. These new technological developments, along with the skills o f trained professionals, will aid in the establishment o f a geodetic control network for cities, states, and counties that plan to implement a Geographic Information System (GIS) or some other Construction Project.
1.3 Establishing geodetic control for Topographical survey
Control surveys establish a common, consistent network of physical points that are the
basis for controlling the horizontal and vertical positions of transportation mprovement projects and facilities. Corridor control surveys ensure that adjacent projects have compatible control. Project control surveys provide consistent and accurate horizontal and vertical control for all subsequent project surveys — photogrammetric, mapping, planning, design, construction, and right of way.
Surveying is based on geodesy. With precise survey instrument, the Earth must be treated as an ellipsoid instead of a sphere. The ellipsoid that is chosen for geodetic survey is called reference ellipsoid. The shape of the Earth, so called geoid, is expressed as an equipotential surface of gravity. Usually, position on the ground is measured in longitude, latitude on the reference ellipsoid and height on the geoid. For convenience to measure the three dimensional values, a lot of monuments whos e longitude, latitude or height is known are settled as referen ce point all over the countries. Control point surveying is a surveying to establish the reference point network, determine the coordinates of a new point based on the reference point network. Some precise measuring instruments such as total station and level are used for the surveying. In addition, rapid development of the space geodesy enables us to establish an international reference frame covering the whole globe.
1.4 Traverse surveying/Control densification
The densification of control points mostly require for setting out construction survey and as well topographical feature survey in construction project mainly Rail way, Road and Industrial construction project.
high-precision GPS/GNSS measurement are being used in the topographical mapping for road, Rail, pipe line, and other surveying related to infrastructure development. The engineer wants actual ground measurement which equal to plane geometrical calculation. However, when utilizing high-precision GPS measurement for topographical location purposes, there is a significant but usually unanticipated problem that must first be addressed if accurate measurements are to be made. Simply put, unless proper correction methods are used, horizontal distances between two locations determined by the GNSS method will differ from the Totalstation method.
There are two way of traversing or control densification a. The conventional method using Theodolite/Totalstation and b. First static measurement using GNSS with scale factor reduction/ground coordinate calculation. Now a day it can be done through mathematical calculation. Measurements that are made by traditional survey methods ie the totalstation. This difference between the two measurements is often referred to as the grid-to-ground problem. It is always identical and requires resolving with mathematical calculation. “Geosystem Corporation” is ready to solve for you.
2.1 Detail Physical feature surveying
Ground-based topographic mapping using real time kinematic global positioning system (RTK GPS) is a useful tool for collecting high resolution elevation data at the landscape level. RTK GPS is mobile, collects data quickly, and measures elevation within an accuracy of 1–5 cm.
In the early 1990s, RTK technology (Real Time Kinematic) was born and the GPS industry hasn’t looked back. RTK allows the user to obtain centimeter-level positioning in real-time. That is the point when using GPS for staking be-came possible and GPS for topographic surveys became very efficient. RTK is the fundamental technology that makes ma-chine control possible.
The basic concept behind RTK is that you have a base station receiver set on a known point somewhere around the project site. The base station receiver sends correction data to the surveyor who is operating the survey receiver (Rover). The correction data is typically sent via UHF or spread spectrum radios that are built specifically for wireless data transfer. The corrections from the base station receiver can be sent to an unlimited number of rovers. Real-time positions on the rover receiver are calculated as fast as 20 times per second or as little as once per second. For staking and topo where the rod person will be carrying the range pole (as in the picture at the right), once per second is plenty fast enough. coordinates used in the design file. Once that is done, you are ready to stake. You can work in Plane or an assumed coordinate system.
2.2 Contour surveying
Topographic map, cartographic representation of the Earth’s surface at a level of detail or scale intermediate between that of a plan (small area) and a chorographic (large regional) map. Within the limits of scale, it shows as accurately as possible the location and shape of both natural and man-made features. Natural features include relief, which is sometimes mistakenly understood to be the sole feature characterizing a topographic map, and hydrographic features, such as lakes and rivers; man-made features include other characteristics of the subject area, such as cities, towns, and villages, and roads, railroads, canals, dams, bridges, tunnels, parks etc.
2.3 Route surveying
A Route Survey is defined as being the required service and product that adequately locates the planned path of a linear project or right of way which crosses a prescribed area of real estate, extending from at least one known point and turning or terminating at another known point. Adequate location shall mean substantial compliance with the conditions and tolerances expressed in this standard. A route survey which defines new or proposed Alignment.
A Route Survey is usually required for the planning of a right of way, the acquisition of fee or easement property and for eventual construction layout work. The location of the facilities within the right of way is often held in respect to the center line or a right of way line. A Route Survey is made on the ground to provide for the location of right of way lines, a centerline, or reference lines in relation to property lines and terrain features.
Route Surveys shall include but are not limited to the proper location, monumentation, description or platting of the following routes:
- Roadways, highways and railroads.
- Transmission lines for communications, fuel, chemical, water and electrical needs.
- Canals, waterways, drainage ditches and sewers.
- View easements, air space easements, ingress and egress easements such as approach routes.
2.4 GIS Mapping
A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data. The key word to this technology is Geography – this means that some portion of the data is spatial. In other words, data that is in some way referenced to locations on the earth.
Coupled with this data is usually tabular data known as attribute data. Attribute data can be generally defined as additional information about each of the spatial features. An example of this would be schools. The actual location of the schools is the spatial data. Additional data such as the school name, level of education taught, student capacity would make up the attribute data.
It is the partnership of these two data types that enables GIS to be such an effective problem solving tool through spatial analysis.
GIS is more than just software. People and methods are combined with geospatial software and tools, to enable spatial analysis, management large datasets, and the display of information in a map/graphical form.
GIS can be used as tool in both problem solving and decision making processes, as well as for visualization of data in a spatial environment. Geospatial data can be analyzed to determine (1) the location of features and relationships to other features, (2) where the most and/or least of some feature exists, (3) the density of features in a given space, (4) what is happening inside an area of interest (AOI), (5) what is happening nearby some feature or phenomenon, and (6) and how a specific area has changed over time (and in what way).
in contrast, involve the representation of the surface of the riverbed or seabed. The end-product is normally a navigational chart. In recent years this branch has become increasingly important with the development of the offshore oil industry. In this case, in addition to the production of charts, the surveyor may be required to position large structures such as oil production platforms. This type of operation would normally necessitate the use of ground and satellite electronic position-fixing equipment.
- Measurement of tides for sea coast work E.g. construction of sea defense works, harbors etc, for the establishment of leveling datam and for reducing sounding.
- Determination of bed depth, by soundings
- For navigation
- Location of rocks, sand bars, navigation light.
- Fro location of under water works volumes of under water excavation etc.
- In connection with irrigation and land drainage schemes.
- Determination of direction of current in connection with
- The location of sewer any pipe or channel that carry waste water out falls.
- Determination of area subject to silt and scour the eating of the place.
- Fornication purposes.
- Measurement of quantity of water and flow of water in connection of water schemes, Power scheme and flood controls.
- Offshore engineering and the shipping industry have continued to expand.
- Drilling rigs (extracting oil, gas etc from deep sea) locating up to 125miles offshore, search for resources particularly oil and gas.
- Offshore islands are constructed of dredged material (to bring material form some where and dump there) to support marine structure.
- Harbor depth up to 80 is required to accommodate larger ships and tankers.
- Containerization has become an efficient and preferred method of cargo handling.
- The demand for recreational transportation ranges from large pleasure cruise ships to small sail bonds.
- Cruise ships to small sail bonds. Hydro graphic surveys are made to a quire and present data on oceans, lakes and harbors. It comprises all surveys made for
- The determination of shore lines, soundings (measurement of depth below the water level) characteristics of bottoms, areas subjected to Scouring and silting, depth available for navigation and velocity as well as characteristics of flow of water.
- The location of lights rocks sand balls, buoys ( anything that floats on the surface of water)
3.2 Multibeam River bed scanning
A multibeam echo sounder is a type of sonar that is used to map the seabed. Like other sonar systems, multibeam systems emit sound waves in a fan shape beneath a ship’s hull. The amount of time it takes for the sound waves to bounce off the seabed and return to a receiver is used to determine water depth. Unlike other sonars, multibeam systems use beamforming to extract directional information from the returning soundwaves, producing a swath of depth readings from a single ping.
During the past decade, the use of multibeam acoustic survey in hydrographic mapping has become increasingly common and accepted. Unlike single beam acoustic survey, Multibeam acoustic survey acquires bathymetric sounding across a swath of water bottom using a collection of acoustic beams, as opposed to a single beam, which ensonifies only the area directly below the depth sounder.
Our survey team is providing multibeam acoustic bathymetric surveys with a specific focus on delivering results to meet the standards of resolution, accuracy, and survey coverage and lead time requirement for every project. GSC carries out multibeam acoustic surveys by Teledyne multibeam echosounders. The multibeam echosounder will equip with RTK GPS base survey system for DGPS corrections. Surveys will also adopt manufactured motion reference unit MRU 333 to measure the precise pitch, roll, and heave of sonar. Our boat supports the deployment of multibeam echo sounders, as well as vibracore sampler, side-scan sonars, RTK GPS receivers, motion reference unit and sound velocity probe.
Key Benefits:Provide high-resolution bathymetry map and a backscatter image of the surveyed area
- Fast data acquisition
- Great data coverage
- Dredging projects
- Rivers, harbor, dam inspection surveys
- Oilfield engineering
- Oceanographic research projects
- Environmental studies
- Hazard surveys
4.1 LiDAR Maping
LIDAR mapping is a unique remote sensing technology that has taken the surveying industry by storm. The acronym “LIDAR” stands for Light Detection and Ranging and describes how the technology uses light in the form of lasers to measure distances. Take-Off Professionals’ data specialists can compile the data collected by a LIDAR system and use it to create exceptionally precise three-dimensional information about a specific area and its characteristics. LIDAR is an ideal system for a variety of industries, including the civil engineering, roadwork and mining industries.
A LIDAR instrument consists of a laser, a scanner and a GPS receiver mounted on a platform. This platform may be mobile or stationary, aerial or terrestrial, based on the needs of the application — the laser, scanner and GPS receiver are the only constants.
There are two types of LIDAR — topographic and bathymetric. These are explained in more detail below:
Topographic: Topographic LIDAR measures distances on land using a near-infrared laser. This is essential for the majority of civil engineering, roadwork and mining operations, which require measuring distances on land.
Bathymetric: Bathymetric LIDAR measures distances in aquatic environments by using a water-penetrating green light laser. This type of LIDAR is commonly used in civil engineering and roadwork applications that require working with underwater environments, such as under bridges.
LIDAR is a highly advantageous survey system for a range of industries, primarily due to the following factors:
Speed: LIDAR can collect a million points of data per second, making it an exceptionally fast method of surveying. Scans of building interiors can last an average of three minutes, but even large-scale surveys can take under an hour to complete, making LIDAR one of the fastest surveying methods available.
Accuracy: LIDAR systems collect extremely dense data with very little room between points. This means that the results are highly accurate, allowing professionals to plot and model natural and man-made geographies with the level of precision they need to plan detailed projects.
Flexibility: When it comes to surveying land with LIDAR, there are plenty of options to choose from. LIDAR systems can be mounted on a variety of platforms based on the needs of an application. For small-scale surveying, a stationary tripod may suffice. LIDAR systems could also be mounted to airplanes, helicopters or drones to survey larger areas. LIDAR data can even be collected at any time of day or night since it uses light as the measurement tool.
Safety: LIDAR systems work relatively quickly and can be operated from a distance, making them a good choice for locations that may be unsafe for human operators to stay for extended periods of time. Their ability to be mounted to aerial crafts also allows them to be used to survey dangerous areas that human surveyors may not normally be able to access.
In addition to these advantages, LIDAR can be integrated with other data sources with relative ease. The key to effectively using LIDAR data, however, is working with a quality data processing company like Take-Off Professionals who can effectively use that data to deliver high-quality 3D models.
The use of LIDAR in civil engineering and surveying is extensive. LIDAR applications in civil engineering and surveying include, but are not limited to, the following:
Design: Civil engineering companies prefer LIDAR technology for its ability to offer extremely accurate results within a short time, which is essential for planning projects around terrestrial limitations.
Evaluation: Civil engineers often use LIDAR to inspect existing buildings and construction products for defects and changes. Comparing the data to previous data can identify changes in structure that would otherwise be difficult to find.
Surveying: Surveyors prefer LIDAR to help them create detailed 3D images, including the landscape and any vegetation or existing structures.
If your Organization uses or is interested in using LIDAR technology, you need a data industry leader to help compile your data and deliver fast and accurate results. Take-Off Professionals can help.
Take-off Professionals is a data industry leader, preparing 3D models and performing quantity takeoff services for a range of industries. We have extensive experience working with LIDAR technology and understand how LIDAR mapping works and how to use it. We are experienced at taking the data collected through LIDAR methods and compiling it into comprehensive, actionable models that companies in the civil engineering, roadwork and mining industries can use. We can help with any type of project from commercial construction to roadwork and mining operations.
Regardless of the system you use, Take-Off Professionals can work with you. We’ve worked with Carlson, Leica, Topcon, Trimble and more and provided our models in a range of final formats to meet the needs of our clients. This makes us an ideal choice for multi-brand fleets.
For over two decades, Take-Off Professionals has provided 3D models for construction companies and related industry professionals, producing about 1,000 machine control models a year. During that time, we’ve maintained a reputation for accuracy, timeliness and attention to detail that speaks for itself. Our knowledge and experience combined with the most advanced and innovative technology in the industry make us the ideal choice for your 3D machine control modeling needs.
4.2 Aerial Photogrammetry (Drone mapping)
Taking aerial photos is one of the most common approaches to mapping out an area. In this process, a camera is mounted on an aircraft and pointed toward the ground with a vertical or near-vertical axis. As the plane follows its flight path, the camera takes multiple overlapping photos, which are then processed in something called a stereo plotter.
The stereo plotter is an instrument that helps determine elevations by comparing two different photos and conducting the necessary calculations. With the help of photogrammetry software, we can process this information and create digital models out of it.
These images are taken from a fixed position on the ground with a camera’s axis parallel to the Earth. Data about the camera’s position, such as its coordinates, are collected at the time the photo is taken. The instruments used for terrestrial photography are often theodolites, though regular cameras are sometimes used as well. Terrestrial photogrammetry for surveying typically requires fewer resources and skilled technicians to accomplish, but it may take longer to cover a large portion of land.
Uses of photogrammetry
The ways that photogrammetry comes to life can vary widely by collection method, data gathered, industry use and compatible technologies.
Some of the products that come from the process include orthomosaics, digital surface models and digital terrain models. An orthomosaic is essentially a birds-eye view of a terrain that adjusts for distortion and can span wide landscapes. Digital surface models and digital terrain models represent surface levels and elevation. Surface models include buildings and trees, while the terrain model gets rid of all of these features, showing the height of the bare earth.
The most common use for photogrammetry is creating maps out of aerial photos. It is cost-effective and accurate, allowing planning entities like architects, local governments and construction workers to make clear, informed decisions about their projects without spending months scouring the landscape. It is also very detailed and can provide an exceptional level of information about an area.
Photogrammetry makes its mark in an array of industries, from medical research to film and entertainment. Here are some of the places you can find it:
We’ve already discussed the applications of photogrammetry in civil surveying, the results of which are used by many entities, including construction crews, governments, building planners and architects. All of the data gathered from photogrammetry inform them about everything from necessary safety measures to potential project results.
In the world of engineering, drone photography helps to evaluate sites for construction, as well as create perspective images and 3D renderings. Engineers can produce images of project results or previews, as well as analyze their current progress.
In the digital age, where 80% to 81% of millennials find their homes on mobile devices, creating attractive, accurate listings can significantly improve the buying experience and their understanding of the purchase. Viewers can see the home from all angles and get a clear idea of what they’re looking at.
Photogrammetry also plays a role in data gathering for military programs. Accurate geo-locational models with low processing times are necessary for understanding a landscape. Aerial imagery and photogrammetric technology can work together to create accurate 3D maps quickly without any human input.
Film and entertainment
Photogrammetry can play a big role in set design and world-building for a variety of films and video games. 3D modeling can bring unique objects to fruition in a virtual world, like cityscapes for action sequences and accurate historical elements, such as statues and buildings. One popular franchise that uses photogrammetry is the “Battlefield” games, which have an art style that works well with these 3D renderings and recreations.
In addition to world-building, photogrammetry can also assist with designing special effects and real sets.
Photogrammetry also plays a part in crime investigation. It can help to document and measure precise data about a crime scene and determine what was physically possible. There are also many photogrammetric experts that can assist in the courtroom.
Construction and mining
Project engineers and contractors can use accurate 3D models to monitor and plan their worksites. The information from a photogrammetric model can help create a smart worksite with sensors and safety features that improve the environment. These models work in tandem with connected vehicles.
Analyzing athlete movements can help coaches and researchers understand more about their activities. They can develop virtual training systems and learn about the physical effort that players expend by tracking their body movements. Topographical maps also come in handy for outdoor athletes, like hikers, mountain climbers, skiers and snowboarders. Mapping remote areas is often easier with the help of photogrammetric technology.
Agriculture and forestry
In agriculture, aerial photos can offer insights into soil quality, irrigation scheduling, nutrition and pests. Farmers can adjust their planting schedules or adjust irrigation and fertilizers with this information. They can also use photogrammetry when assessing growth and crop damage after storms or floods.
Researching and managing forests becomes significantly easier with the help of photogrammetry. It can produce models to analyze various aspects of a forest, like timber volume and height, to better understand the development of a forest