ENGE253
Control Survey
Syllabus
- Introduction (4 hours)
- Overview of geodetic surveying
- Horizontal and vertical controls
- Importance of horizontal and vertical controls
- Historical development and evolution of control surveys
- Applications of control surveys in geomatics engineering
- Vertical Control Survey (12 hours)
- Definition and significance of vertical control
- Types of vertical control surveys: Levelling, trigonometric, and GNSS-based vertical control
- Techniques for vertical control survey
- Obstacles in establishing vertical controls
- Vertical control networks in Nepalese context
- Modern height reference system and frame
- Advantages of modern height reference system
- Error Sources and adjustments in vertical control
- Application of vertical control surveys
- Vertical control standards in Nepal (Red book)
- Triangulation and Trilateration (12 hours)
- Introduction to triangulation
- Triangulation figures and different framework/systems
- Classification of triangulation and specifications in context of Nepal
- Strength of figure
- Field procedure in triangulation: Reconnaissance, monumentation, signaling, observation and recording
- Different errors in base line measurement and their corrections
- Satellite station and reduction to center
- Trilateration and its principle
- Field procedure in trilateration: Reconnaissance, monumentation, signaling, observation and recording
- Errors in trilateration and field precautions
- Traversing (12 hours)
- Traverse and principle of traversing
- Open and closed traverse
- Classification of traverse and specification
- Different methods of traversing
- Observation of traverse angles and its different methods
- Observation of traverse lengths
- Angle adjustment and bearing computation
- Departure, Latitude and its computation (Gale's traverse table)
- Traverse adjustment (Bowditch, transit, axis and graphical method)
- Omitted measurements in its different case
- Resection and Intersection (8 hours)
- Definition, principles, purpose and scope
- Analytical intersection and resection
- Two points and three-point resection and their significance
- Instruction on field application
- Field Operation (Reconnaissance, monumentation, signaling, observation, recording, computation and adjustment)
- Field precautions
- Geodetic Control Networks (8 hours)
- Geodetic control networks overview
- Datum and reference systems
- Horizontal datum (WGS84, NAD83)
- Vertical datum (NAVD88)
- Establishment and maintenance of geodetic control networks
- Use of global navigation satellite systems (GNSS) in geodetic control surveys
- History of geodetic network in Nepal
- Establishment of Laplace station
- Processing and adjustment of geodetic data
- National Gravity Network (4 hours)
- History
- Nagarkot datum
- Gravity stations in Nepal
- Use and extension of national gravity station
Practicals
- Leveling: Trigonometric levelling; Precise levelling; Profile and cross section levelling; Reduction of level
- Traversing: Reconnaissance and selection of stations; Preparation of description card (D-Card); Angle observation; Traverse computation; Traverse adjustments
- Triangulation: Reconnaissance and selection of stations; Observation and recording; Computation and adjustment
- Intersection and resection