Surveying and Geomatics Engineering: Principles, Technologies, and Applications

Surveying engineering may be regarded as a specialty within the broader professional practice of engineering and includes all surveying and mapping activities required to support sound conception, planning, design, construction, maintenance, and operation of engineered projects. This chapter introduces the key concepts of surveying engineering that are discussed in subsequent chapters. These include the leading role of ASCE's Surveying and Geomatics Division in surveying engineering, and more broadly, geomatics, the “mathematics of the earth”; the role of surveying engineers in providing an increasing level of sophisticated mapping, positioning, control, monitoring, and in some cases, navigation information; and the role in the United States of each state's licensing board in determining, in conjunction with the state legislature, what the definition of surveying entails.

This chapter introduces Geodesy as both a science and an art that includes activities devoted to determining the size and shape of the Earth, defining the location of objects in/on/near the Earth, and understanding the forces of nature governing the movement of those objects. The horizontal and vertical control marks are referenced to various National Geodetic Survey-defined data. The reliance in the United States on the integrity of the geodetic survey control networks for development of the physical infrastructure is explored. A spherical Earth model is presented that utilizes equations of spherical trigonometry; this model has applications in disciplines such as navigation and geography. Geometrical models used in geodesy that are embodied in various projected coordinate systems are described. The geometrical geodesy model uses the ellipsoid as the basis for computations. A geodetic inverse computation consists of finding the direction and distance from one known point to another based upon a specified reference ellipsoid.

Coordinate systems are an integral part of modern surveying and geomatics. This chapter focuses primarily on georeferenced coordinate systems, or spatial reference systems, which range in extent from global to local. When a map projection is associated with a specific geodetic datum, it is called a projected coordinate system (PCS). State plane coordinate systems are multizone systems of conformal PCSs in which each zone is designed using transverse mercator, lambert conformal conic, or Hotine oblique mercator projections. Map projection linear distortion is manifested as a difference in distance between a pair of projected coordinates and the true horizontal distance at the surface of the Earth. Also explored are large-scale conformal projected coordinate systems for surveying engineering, which became common in the United States after the creation of the State Plane Coordinate System in the 1930s by the National Geodetic Survey.

This chapter provides an overview of a wide range of coordinate transformations used in surveying engineering. These transformations include transformation of coordinates, which can range from modifications of a local planar system for a project site to complex geodetic operations at a continental or global scale. Three-dimensional data collection techniques, usually used in modern surveying with equipment such as total stations, Global Navigation Satellite Systems, and laser scanners are evaluated. Also discussed are applications of horizontal coordinates; this mathematical operation is often performed so that one set of coordinates can be made to match another set. The four-parameter, two-dimensional transformation can be generalized to allow scale to vary with direction, as well as to allow skewing of the coordinate axes, to create a horizontal 6-parameter affine transformation. Finally, grid-based transformations are described; these consist of regular grids of coordinate differences where the differences at locations between grid points are interpolated.

This chapter investigates observational error sources, discusses how to adjust the observations so that the final adjusted unknowns are the most probable values for the given set of observations, and explores statistical procedures that can be used to identify systematic errors and random errors after an adjustment. Also explored are errors resulting from least squares adjustments, the simultaneous solution of a set of equations that represents observations in terms of a set of unknown parameters and renders the sum of the squared residuals as a minimum. Following a least squares adjustment, error propagation principles are used to develop postadjustment statistics. Modern map accuracy standards are based on a statistical analysis of a check survey's coordinates, as opposed to map coordinate values.

Global Navigation Satellite Systems (GNSS) refer to any satellite systems that provide positioning, navigation, and timing on a regional or global basis, as well as satellite systems in development that will likely reach similar capability in the near future. Most GNSS surveying relies on the idea of relative positioning. This chapter focuses on the current Global Positioning System (GPS) constellation, which consists of 24 satellites under full operational capability. The control segment is comprised of government tracking and uploading facilities distributed around the world. GPS positions are based on the measurement of the ranges from the receivers to the satellites. Also discussed are static GPS surveying applications in control surveys, as well as the Quasi-Zenith Satellite System, which is intended to provide satellites in highly elliptical orbits that are inclined and geosynchronous to improve satellite positioning, navigation, and timing services in urban canyons and mountainous areas.

Differential leveling is the process by which the elevation difference between points is measured directly. Levels are designed to project a horizontal plane by aligning a telescope at right angles to the vertical at the location of the instrument. Specific topics addressed in this chapter include: the criticality of a properly focused telescope for quality observations, especially when using digital levels; use of tripods to hold surveying equipment in a stable location during operation; and the modern total station, a surveying instrument that integrates an angle-turning instrument, a distance measuring instrument and a data recording and computation capability. Leveling processes can be divided into separate categories according to how measurements are gathered. The purpose of adjustment is twofold: to provide a consistent set of adjusted measurements, so that all information derived from the measurements is consistent; and to provide a maximum probability estimate of the true values of the measurements.

Terrestrial laser scanning (TLS) has become a powerful, new surveying technology to support a wide range of engineering applications that include topographic mapping, asset management, deformation monitoring, quantity calculations, and safety evaluations. This chapter introduces TLS, describes common applications of TLS in Civil Engineering, and provides an overview of several types of TLS systems. The characteristics of TLS systems that differ from other lidar platforms such as airborne and mobile platforms are discussed. A TLS workflow is outlined, focusing on such important steps as planning, field procedures, registration and georeferencing, processing, and analysis. A variety of currently available terrestrial laser scanners are evaluated, and some common limitations, errors, and artifacts in TLS data are identified. Two types of targets to be utilized in scanning are discussed: transformation control targets and validation control targets.

Mobile terrestrial laser scanning (MTLS) systems collect accurate, detailed, three-dimensional point cloud data more efficiently and more safely for road or rail projects than do many other approaches available to the survey engineer. This chapter describes processes and important considerations for the various stages of the MTLS workflow, including planning, preliminary site surveys, data acquisition, georeferencing, postprocessing, computations and analysis, and packaging and delivery. Acquisitions should be completed by both a driver and an operator for safety reasons. Quality control should be planned and implemented in each stage of the mobile lidar workflow. Significant differences between indoor mobile mapping systems and outdoor systems are explored. Future expansion of kinematic surveying and mapping systems is then discussed.

This chapter explores the use of photogrammetry by federal agencies such as the United States Geological Survey, state agencies, and private surveying and engineering companies to develop maps at various scales and for a variety of purposes. The development of two more essential photogrammetric products, digital elevation models, and orthophotos is reviewed. Most digital cameras have nonsquare formats, and thus, the angular field of view is specified for both the along-track and across-track dimensions. Analytical photogrammetry can be considered a suite of methods to calculate three-dimensional (3D) coordinates of points from photography using rigorous mathematical models, and in general, the solution of large redundant systems of equations using least squares. Aerial laser scanning, commonly referred to as airborne light detection and ranging, is introduced as a method to rapidly collect topographic data over large areas at submeter 3D spatial resolution. Finally, applications of unmanned aircraft systems in aerial photogrammetry and remote sensing are assessed.

This chapter discusses the importance of correctly identifying the necessary types of control at the beginning of a survey project, provides recommendations on how to find available local and geodetic control, and presents available tools for establishing new, denser control for a project. The Online Positioning Service of the National Geodetic Survey (NGS) is introduced. NGS provides two kinds of geodetic control for tying surveys to the National Spatial Reference System: active control as part of the NOAA Continuously Operating Reference Station Network; and passive control consisting of disks or rods. Surveying engineering control is categorized as horizontal control or vertical control. Confusion can be avoided if the engineering manager directs the surveying engineer immediately to the appropriate geometric and/or vertical control at the onset of the project. Local control may have coordinates in a local or legacy coordinate system.

This chapter details equipment processes used in construction surveys to establish locations and evaluate and estimate quantities for construction activities. The preconstruction phase can include a location survey of the project area, preliminary survey, or location survey. Field work during construction includes tying into existing horizontal and vertical control points and augmenting and replacing control points to control the construction project. The importance of vertical control in all construction projects is illustrated. The construction survey equipment consists of the total station and level. Construction staking is performed to ensure a project is built according to the engineering design plans. Slope stakes are set to control the construction of earthwork slopes. Earthwork computations involve the calculation of earthwork volumes, the determination of final grades, the balancing of cuts and fills, and the planning of the most economical material. The machine guidance and control system involves the integration of positioning tools with construction machinery.

In this chapter, survey records are considered to include a company's or an agency's surveying and graphic standards; the construction documents or work order describing the project itself and the surveying engineering services to be provided; numeric data from both field surveys and calculations; and graphic data in the form of both field notes and maps. Surveying engineering must often meet specific contract provisions or conform to the requirements listed in an agency, industrial work order, or authorization. Drafting standards employed by the company or required by an agency govern the preparation and distribution of graphic records of the survey. Use of the State Plane Coordinate System as a basis for surveying in the United States is explored, as well as data adjustment for rational distribution of corrections among field observations. Also described are several ways of documenting control marks and including them in survey records.

This chapter introduces Geographic Information System (GIS) and Building Information Modeling (BIM) techniques and summarizes their various applications in civil engineering. A BIM is a digital representation of the physical and functional characteristics of a facility. Applications of coordinate systems in GIS/BIM are reviewed. An overview of the computing hardware and software necessary for GIS and BIM technologies is provided. Immersive Visualization Technologies such as Virtual Reality, Augmented Reality, and Mixed Reality as well as their implementation with GIS/BIM are evaluated. Querying is a particularly critical component of a database, and as such, is an important and useful operation in GIS. Interpolation is the process of finding/predicting values based on other known values in the vicinity. The benefits of using BIM in the building construction industry are discussed in the context of adaptation of these techniques by heavy civil contractors and several departments of transportation.

This chapter presents the basic elements of a legal contract, followed by special considerations related to designing professional contracts, some basic contract clauses that should be included in a design professional's agreement, and a specific clause to be included in a design professional's employment agreement with an employer. for a contract to be enforceable by a civil court of law are discussed: offer, acceptance, consideration, consent, capacity, legality, and writing. The parties to a contract must give their consent to contract freely. A design professional's contact will incorporate by reference a “prime agreement” between the design professional's client, and the owner. Indemnitees should be limited to the client, its affiliates, and their respective officers, directors, and employees.