Learning objectives
The course aims not only to transmit a specific baggage of basic topographical knowledge, but also to develop a series of engineering skills in the student. Specifically at the end of the activities the student is asked to demonstrate: - to know the measurement errors and to be able to evaluate their effects on the results of the calculations involving the measures; - to be able to evaluate the order of magnitude of the expected results on the basis of simple rules and calculations; - to be able to ascertain the congruence of a set of measurements (levelling, polygonal, etc.), verifying whether they are in tolerance according to the instrumental accuracies;- know how to apply knowledge on error propagation to assess the appropriateness of a measurement scheme for design purposes;- to be able to calculate the coordinates of the points of a planimetric network from the measurements;- to know how to apply statistical inference to evaluate the significance of variations in time of measurements or coordinates in the control of displacements or deformations. - to know the topographic instrumentation (accuracy, flow rates, systematic errors) including the GPS, being able to choose the most suitable for the purposes of a given survey. The course includes group activities that contribute to developing communication and comparison skills; in addition, the practical tests must be accompanied by a written report commenting on the results.
Prerequisites
Calculus and geometry: derivatives, integrals, linearization of functions, solution of non linear equations systems, matrix algebra.
Course unit content
Surveying is concerned with determining the position of points of the Earth surface w.r.t. a geodetic datum with controlled accuracy. Surveys are needed to produce technical maps, control displacements and deformation of large structures, vertical and
horizontal terrain movements. Staking (construction surveying) is fundamental in road and industrial plants construction, land plot subdivision, etc.To achieve these results, Surveying uses instruments and makes measurements from which, defined the reference system (global, local) and the cartographic projection, the coordinates of the points are derived. To take account of measurement uncertainty, probability and statistical data analysis are used to design the survey and evaluate measurement results.Lessons topics: the definition of reference and coordinates systems on a local and global scale; the calculation of coordinates from measurements; the cartographic representation of the Earth's surface; the treatment of observations, including hypothesis testing; the characteristics of topographic instrumentation and methods of measurement; the main topographical operations for civil engineering.
Full programme
Geodesy and Reference systems.
Surveying basic concepts. Geoid and Ellipsoid. Reference systems,
coordinate systems, geodetic datum. Coordinate transformation and
datum transformation. Elements of geodesy.
Cartography
Classification of map projections. Gauss projection and its use in geodetic
computations. UTM projection. Map production in Italy at different map
scales. Cadastral maps.
Error theory and statistical analysis of data.
Errors. Probability and random variables. Error propagation law. Error
ellipse. Inference: parametric tests and confidence interval. Least
squares adjustment of observations. Tests on standardized residuals and
significance of parameters. Measurement reliability.
Surveying instruments and surveying methods.
Total stations, levels; measurement of angles, distances, height
differences.
Geodetic and topographic networks.
Observation equations of horizontal and height networks. Network
simulation and adjustment. Georeferencing and co-registration of
networks.
GPS.
System description. Pseudo-range and phase observations. Systematic
errors and modeling techniques. Accuracy of absolute, relative and
differential positioning in kinematic and static surveys. GPS network design.
ITRF and ETRF frames and trasformation to national datum and
orthometric heights. GPS permanent stations networks.
Application of Surveying to civil engineering
Use of maps in engineering projects. Road construction and building
construction surveys. Deformation and displacement monitoring in
building, bridges; landslides displacement control
Bibliography
Recommended texbooks
B. Hofmann-Wellenhof, H. Lichtenegger and J. Collins - Global positioning system : theory and practice. Available in the
Biblioteca politecnica di Ingegneria e Architettura.
Alfred Leick - GPS satellite surveying
Course material (slides of the lectures, lecture notes on statistical data analysis, exercices, etc.) can be found at http://elly.dia.unipr.it,under Lauree Triennali Ingegneria Civile e Ambientale TOPOGRAFIA.Registration mandatory.
All the material is usually available at the beginning of the course, but it is also updated during the lessons, especially as regards the data to be used in the exercises.
Teaching methods
Lectures, possibly with questions to the audience. Numerical exercises always follow the theory; sometimes the solution of a standard exercise is first illustrated and commented, sometimes students are left to themselves to find how to apply the theory to solve the problem.
The ratio between hours of frontal lesson and exercise is approximately 2:1, excluding the hours dedicated to the illustration of the instruments.
Space is also given to activities in groups, in the control survey project and in the survey in the countryside. In this case one or more frontal lessons or practical demonstrations illustrate the motivations and problems of the topic to be addressed. The groups work autonomously and can communicate with the teacher in case of need; as a rule the teacher supervises the initial phases of the survey in the countryside. The solution of the numerical tasks and questions is usually illustrated in the classroom or through the publication on the Elly platform of the exercise resolved. The evaluation criteria for the group work are explained in the presentation of the objectives; the evaluation of the reports and results is discussed at the discretion of the groups.
Assessment methods and criteria
The examination can be either by solving numerical exercises and
answering to written questions along the semester or by a discussion at
the end of the semester.
The written questions are in the form of “True or False” questions; aim to
evaluate the knowledge base and count for about 25% of the total score.
Solving the exercices highlights knowledge, understanding and ability to
apply them; they count for about 50% of the score. Homework and
teamwork in the field survey highlight ability to apply knowledge and
understanding as well as communication skills; they count for about 25%
of the score.
The oral examination starts with a simple exercise with computations;
solving it is a prerequisite to continue the examination; it amounts to about 10% of the total score. Then three aspects about theoretical, methodological and practical aspect of surveying are inquired; each answer to these questions contribute to the score by about 30%.
Other information
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