Surveying and Geomatics Textbook PDF

 Text Book on Surveying and Geomatics By P.K. GARG Professor Civil Engineering Department Indian Institute of Technology Roorkee, Roorkee &...

 Text Book on Surveying and Geomatics By P.K. GARG Professor Civil Engineering Department Indian Institute of Technology Roorkee, Roorkee & Former, Vice Chancellor Uttarakhand Technical University, Dehardun Reviewer RAAJ RAMSANKARAN Associate Professor Civil Engineering Department Indian Institute of Technology Bombay Mumbai ii BOOK AUTHOR DETAILS Prof. P K Garg, Professor-HAG, Civil Engineering (CE), IIT Roorkee. Email ID: [email protected] BOOK REVIEWER DETAILS Prof. Raaj Ramsankaran, Associate Professor, Department of Civil Engg., IIT Bombay. Email ID: [email protected] BOOK COORDINATOR (S) – English Version 1. Dr. Amit Kumar Srivastava, Director, Faculty Development Cell, All India Council for Technical Education (AICTE), New Delhi, India Email ID: [email protected] Phone Number: 011-29581312 2. Mr. Sanjoy Das, Assistant Director, Faculty Development Cell, All India Council for Technical Education (AICTE), New Delhi, India Email ID: [email protected] Phone Number: 011-29581339 November, 2022 © All India Council for Technical Education (AICTE) ISBN : 978-81-959863-7-8 All rights reserved. No part of this work may be reproduced in any form, by mimeograph or any other means, without permission in writing from the All India Council for Technical Education (AICTE). Further information about All India Council for Technical Education (AICTE) courses may be obtained from the Council Office at Nelson Mandela Marg, Vasant Kunj, New Delhi- 110070. Printed and published by All India Council for Technical Education (AICTE), New Delhi. Laser Typeset by: Printed at: Disclaimer: The website links provided by the author in this book are placed for informational, educational & reference purpose only. The Publisher do not endorse these website links or the views of the speaker / content of the said weblinks. In case of any dispute, all legal matters to be settled under Delhi Jurisdiction, only. iii iv  Acknowledgement The author is grateful to the authorities of AICTE, particularly Prof. M. Jagadesh Kumar, Chairman; Prof. M. P. Poonia, Vice-Chairman; Prof. Rajive Kumar, Member-Secretary and Dr Amit Kumar Srivastava, Director, Faculty Development Cell for their planning to publish the books on (Surveying and Geomatics). We sincerely acknowledge the valuable contributions of the reviewer of the book Prof. RAAJ Ramsankaran, Associate Professor, Civil Engineering Department, IIT Bombay, Mumbai, to make the contents and subject matter more meaningful. It is hoped that this book will cover the AICTE Model Curriculum and the guidelines of National Education Policy (NEP) -2020. I am extremely grateful to my family members; Mrs Seema Garg, Dr Anurag Garg, Dr Garima Garg, Mr Hansraj Aggrawal, Ms Pooja Aggrawal and Master Avyukt Garg, and all relatives & friends for their understanding, continuous encouragement, moral support and well-wishes. Above all, I express my gratitude to Almighty God for offering all blessings and giving me enough strength to work hard to complete the Book on time, as planned. This book is an outcome of various suggestions of AICTE members, experts and authors who shared their opinion and thought to further develop the engineering education in our country. Acknowledgements are due to the contributors and different workers in this field whose published books, review articles, papers, photographs, footnotes, references and other valuable information enriched us while writing this book. Finally, I like to express our sincere thanks to the publisher, M/s. XXXXXXXXXXXXXXXXXXXXX whose have cooperated to publish this book in a timely manner. (P K Garg) Professor Civil Engineering Department Indian Institute of Technology Roorkee & Former, Vice Chancellor Uttarakhand Technical University, Dehardun v  Preface The present book is an outcome of the fast developments which are taking place in Surveying and Geomatics in terms of their applications in wide range of disciplines. The objective of writing this book is to make the engineering students aware about the basics and applications of various tools and techniques used in surveying and geomatics. The book provides a wide coverage of essential topics as recommended by the AICTE. Efforts are made to explain the fundamentals of the surveying approaches in a simple way. Presently, there is an acute shortage of books which cover all the topics in a single book, and therefore the students have to consult many books to understand all the topics. This book presents a comprehensive matter on surveying and geomatics tools and techniques so that students are able to understand many topics from a single book. While preparing the manuscript, emphasis has been laid on the basic principles and field procedure to use various surveying equipment. To provide better understanding, theory has been presented in a very logical and systematic manner with several illustrations. The book covers medium and advanced level numerical problems to test the understanding of the students. It is hoped that the book will inspire the students of civil engineering, geomatics engineering, geology and geography, image processig, to learn and discuss the new ideas in surveying and geomatics, and will contribute to the development of a solid foundation of the subject, and make their career in surveying profession. The author will be thankful to all the constructive comments and suggestions for further improvement of the book. (P K Garg) Professor Civil Engineering Department Indian Institute of Technology Roorkee & Former, Vice Chancellor Uttarakhand Technical University, Dehardun vi  Outcome Based Education For the implementation of an outcome based education the first requirement is to develop an outcome based curriculum and incorporate an outcome based assessment in the education system. By going through outcome based assessments evaluators will be able to evaluate whether the students have achieved the outlined standard, specific and measurable outcomes. With the proper incorporation of outcome based education there will be a definite commitment to achieve a minimum standard for all learners without giving up at any level. At the end of the programme running with the aid of outcome based education, a students will be able to arrive at the following outcomes: PO-1: Engineering knowledge: Apply the knowledge of mathematics, science, engineering fundamentals, and an engineering specialization to the solution of complex engineering problems. PO-2: Problem analysis: Identify, formulate, review research literature, and analyze complex engineering problems reaching substantiated conclusions using first principles of mathematics, natural sciences, and engineering sciences. PO-3: Design/development of solutions: Design solutions for complex engineering problems and design system components or processes that meet the specified needs with appropriate consideration for the public health and safety, and the cultural, societal, and environmental considerations. PO-4: Conduct investigations of complex problems: Use research-based knowledge and research methods including design of experiments, analysis and interpretation of data, and synthesis of the information to provide valid conclusions. PO-5: Modern tool usage: Create, select, and apply appropriate techniques, resources, and modern engineering and IT tools including prediction and modeling to complex engineering activities with an understanding of the limitations. PO-6: The engineer and society: Apply reasoning informed by the contextual knowledge to assess societal, health, safety, legal and cultural issues and the consequent responsibilities relevant to the professional engineering practice. PO-7: Environment and sustainability: Understand the impact of the professional engineering solutions in societal and environmental contexts, and demonstrate the knowledge of, and need for sustainable development. PO-8: Ethics: Apply ethical principles and commit to professional ethics and responsibilities and norms of the engineering practice. PO-9: Individual and team work: Function effectively as an individual, and as a member or leader in diverse teams, and in multidisciplinary settings. PO-10: Communication: Communicate effectively on complex engineering activities with the engineering community and with society at large, such as, being able to comprehend and write effective reports and design documentation, make effective presentations, and give and receive clear instructions. PO-11: Project management and finance: Demonstrate knowledge and understanding of the engineering and management principles and apply these to one’s own work, as a member and leader in a team, to manage projects and in multidisciplinary environments. PO-12: Life-long learning: Recognize the need for, and have the preparation and ability to engage in independent and life-long learning in the broadest context of technological change. vii  Course Outcomes After completion of the course the students will be able to: CO-1: Describe various classifications of surveying, purpose and the equipment used for survey work. CO-2: Carry out linear, height and angular measurements from various surveying instruments and compute the coordinates, including plotting of ground details to prepare maps. CO-3: Apply computations for setting out horizontal and vertical curves on the ground using various methods. CO-4: Use of various modern surveying equipment for digital field data collection and analyisis with greater speed and accuracy. CO-5: Apply the concepts of Photogrammetry for scale, relief displacement and height determination as well as providing horizontal and vertical controls for engineering projects. CO-6: Analyze different types of optical remote sening images for creation of accurate thematic maps. Course Expected Mapping with Programme Outcomes outcomes (1- Weak correlation; 2- Medium correlation; 3- Strong correlation) PO- PO- PO- PO- PO- PO- PO- PO- PO- PO- PO- PO- 1 2 3 4 5 6 7 8 9 10 11 12 CO-1 3 2 2 2 1 1 1 1 1 1 1 1 CO-2 3 2 2 2 1 2 1 1 2 2 2 1 CO-3 3 3 2 2 1 2 1 1 2 2 2 1 CO-4 3 3 3 3 3 2 1 1 2 2 2 1 CO-5 3 3 2 2 2 2 2 1 2 2 2 1 CO-6 3 3 3 3 3 2 2 1 2 2 2 1 viii  Guidelines for Teachers To implement Outcome Based Education (OBE) knowledge level and skill set of the students should be enhanced. Teachers should take a major responsibility for the proper implementation of OBE. Some of the responsibilities (not limited to) for the teachers in OBE system may be as follows: Within reasonable constraint, they should manoeuvre time to the best advantage of all students. They should assess the students only upon certain defined criterion without considering any other potential ineligibility to discriminate them. They should try to grow the learning abilities of the students to a certain level before they leave the institute. They should try to ensure that all the students are equipped with the quality knowledge as well as competence after they finish their education. They should always encourage the students to develop their ultimate performance capabilities. They should facilitate and encourage group work and team work to consolidate newer approach. They should follow Blooms taxonomy in every part of the assessment. Bloom’s Taxonomy ix  Guidelines for Students Students should take equal responsibility for implementing the OBE. Some of the responsibilities (not limited to) for the students in OBE system are as follows: Students should be well aware of each UO before the start of a unit in each and every course. Students should be well aware of each CO before the start of the course. Students should be well aware of each PO before the start of the programme. Students should think critically and reasonably with proper reflection and action. Learning of the students should be connected and integrated with practical and real life consequences. Students should be well aware of their competency at every level of OBE x  List of Abbreviations Abbreviations Full Form Abbreviations Full form AI Artificial Intelligence LISS Linear Imaging Self Scanning Sensor ALISS Advanced Linear Imaging NavIC Navigation with Indian Scanning Sensor Constellation ALS Airborne Laser Scanner NAVSTAR Navigation Satellite Timing and Ranging ANN Artificial Neural Networks NDVI Normalized Difference Vegetation Index AS Anti-Spoofing mode NIR Near Infrared ASTER Advanced Spaceborne Thermal NOAA National Oceanic and Emission and Reflection Atmospheric Administration Radiometer AVHRR Advanced Very High NRSC National Remote Sensing Resolution Radiometer Centre AVIRIS Airborne Visible/infrared OCM Ocean Colour Monitor Imaging Spectrometer AWiFS Advanced Wide Field Sensor OLI Operational Land Imager BEIDOU Beidou Navigation Satellite PAN Panchromatic System BIM Building Information Modelling PC Point of Curvature BM Bench Mark PI Point of Intersection BS Back Sight POC Point on Curve C/A code Course/Acquisition-code POT Point on Tangent CP Change Point PP Principal Point DEM Digital Elevation Model PT Point of Tangency DGPS Differential GPS RADAR RAdio Detection And Ranging DN Digital Number RBV Return Beam Videcon DoD Department of Defence RGB Red, Green, Blue DOP Dilution of Precision RL Reduced Levels DPW Digital Photogrammetric rms Root Mean Square Workstation DSM Digital Surface Model MIR Middle Infrared DSS Decision Support Systems MODIS Moderate Resolution Imaging Spectroradiometer DTM Digital Terrain Model MSL Mean Sea Level ERTS Earth Resources Technology MSS Multispectral Scanner Satellite EDM Electronic Distance NDVI Normalised Difference Measurement Vegetation Index EMR Electro-magnetic Radiations OTF-AR On-The-Fly–Ambiguity Resolution EMS Electro-magnetic Spectrum PCA Principal Component Analysis ETM Enhanced Thematic Mapper P-Code Precision-code ETM+ Enhanced Thematic Mapper PPS Precision Positioning Plus Signals FCC False Colour Composite PRN Pseudorandom Noise FS Fore Sight QZSS Quasi-Zenith Satellite System xi GCP Ground Control Points RINEX Receiver Independent Exchange Format GDOP Geometric Dilution of Precision RTK Real-Time Kinematic GIS Geographical Information SA Selective Availability System GMS Geostationary Meteorological SAR Synthetic Aperture Radar Satellite GOES Geostationary Operational SoI Survey of India Environmental Satellite GPR Ground Penetrating Radar SPOT Système Pour l’Observation de la Terre GPS Global Positioning System SPS Standard Positioning Signals HE Histogram Equalization SRTM Shuttle Radar Topography Mission HRG High Resolution Geometrical SST Sea Surface Temperature HRV High Resolution Visible SWIR Short Wave Infrared HR-VIR Visible & Infrared High- TCT Tasselled Cap Resolution Transformations IFOV Instantaneous Field of View TIR Thermal Infrared ILWIS Integrated Land and Water TLS Terrestrial Laser Scanner Information Management IoT Internet of Things TM Thematic Mapper IR Infrared UAV Unmanned Aerial Vehicle IRNSS Indian Regional Navigation UTM Universal Transverse Satellite System Mercator IRS Indian Remote Sensing UV Ultraviolet Satellites IS Intermediate Sight VI Vegetation Indices ISODATA Iterative Self-Organizing Data WAAS Wide Area Augmentation Analysis Technique System GLONASS Global Navigation Satellite WGS-84 World Geodetic System- System 1984 GNSS Global Navigation Satellite WiFS Wide Field Sensor System LANDSAT Land Satellites LiDAR Light Detection and Ranging xii  List of Figures Unit 1 Surveying Fig. 1.1: First principle of surveying: working from whole to part 5 Fig. 1.2: Second principle of surveying 6 Fig. 1.3: The 36 inch theodolite used in the Indian triangulation 7 Fig. 1.4: Surveying based on equipment and tools 11 Fig. 1.5: A typical linear scale 15 Fig. 1.6: A typical toposheet 16 Fig. 1.7: Survey stations and survey lines 18 Fig. 1.8: (a) Survey chain, and (b) Measuring tape 23 Fig. 1.9: Specifications of a ranging rod 25 Fig. 1.10: Direct ranging 26 Fig. 1.11: Reciprocal ranging 26 Fig. 1.12: Representation of whole circle bearing 28 Fig. 1.13: Representation of whole circle bearing into reduced bearing 28 Fig. 1.14: Cross-sectional diagram of a prismatic compass 39 Fig. 1.15: Fore bearing and back bearing 31 Fig. 1.16: Determination of magnetic meridian 31 Fig. 1.17: Relationship between horizontal angles and bearings 32 Fig. 1.18: Representation of various terms 35 Fig. 1.19: Line of collimation 35 Fig. 1.20: Various levelling staff 37 Fig. 1.21: Tilting level 38 Fig. 1.22: Various components of an Auto level 39 Fig. 1.23: (a) Digital level, and (b) Bar code leveling staff 40 Fig. 1.24: Self-levelling rotary laser, (b) Laser detector and levelling staff 42 Fig. 1.25: Setting up a tripod 42 Fig. 1.26: Levelling the base of the instrument using three foot screws 43 Fig. 1.27: Various diaphragms 43 Fig. 1.28: Height of instrument method 44 Fig. 1.29: Simple levelling observations 45 Fig. 1.30: Differential levelling observations 45 Fig. 1.31: Longitudinal and cross-section profiles observations 46 Fig. 1.32: Reciprocal levelling observations (a) from side A and (b) from side B 47 Fig. 1.33: Representation of contours 50 Fig. 1.34: Contours depicting various shapes of the ground 52 Fig. 1.35: Area of trapezoids 55 Fig. 1.36: Computation of area of closed irregular polygon 57 Fig. 1.37: Prismoidal section 58 Fig. 1.38: Accessories of plane table survey 60 Fig. 1.39: Various part of a vernier theodolite 62 Fig. 1.40: (a) Reiteration method (b) Repetition method 64 Fig. 1.41: (a) Measurement of vertical angle AOA’, and (b) Angle of elevation and angle of 67 depression Fig. 1.42: Prolonging a line with a theodolite 67 Fig. 1.43: Closed traverse (left) and open traverse (right) 68 Fig. 1.44: Exterior angles (clockwise traverse) and interior angles (anti-clockwise traverse) 69 Fig. 1.45: Deflection angle measurement in open traverse 69 Fig. 1.46: Stadia diaphragm commonly used in tacheometers 71 Fig. 1.47: Staff held vertical at higher elevation 72 Fig. 1.48: Staff held vertical at lower elevation 72 Fig. 1.49: Measurement when the object is accessible 74 xiii Fig. 1.50: Measurement when object is inaccessible 75 Fig. 1.51: The base of tower is inaccessible and instrument is kept in different vertical planes 76 Fig. 1.52: Comutation of latitude and departure of a line 77 Fig. 1.53: Representation of closing error 79 Fig. 1.54: Triangulation survey scheme 81 Fig. 1.55: (a) Chain of triangles, (b) quadrilaterals, and (c) centred polygons. 82 Fig. 1.56: Various lines in a triangulations scheme 84 Fig. 1.57: Intervisibility between two triangulation stations 85 Fig. 1.58: Angle observations between triangulation stations, and (b) Axis signal corrections 86 Unit 2 Curves Fig. 2.1: Various types of curves 112 Fig. 2.2: Various curves (a) simple, (b) compound, (c) reverse, and (d) transition curve 113 Fig. 2.3: Representations of a simple circular curve 114 Fig. 2.4: Representation of the degree of curve 115 Fig. 2.5: Setting out the curve by ordinates from the long chord 117 Fig. 2.6: Setting out the curve by successive bisection of arcs 118 Fig. 2.7: Setting out the curve by radial offsets from the tangents 119 Fig. 2.8: Setting out the curve by offsets perpendicular to the tangents 120 Fig. 2.9: Setting out the curve by offsets from the chord produced 120 Fig. 2.10: Curve setting by Rankine’s method 123 Fig. 2.11: Curve setting by two theodolite method 125 Fig. 2.12: A compound curve 126 Fig. 2.13: A reverse curve 128 Fig. 2.14: Elements of a reverse curve 129 Fig. 2.15: A typical transition curve 131 Fig. 2.16: Various types of transition curves 132 Fig. 2.17: Depiction of super-elevation 133 Fig. 2.18: Characteristics of a transition curve 135 Fig. 2.19: Sight distance in vertical summit curve 137 Fig. 2.20: Types of vertical curves 139 Fig. 2.21: Elements of a summit vertical curve 140 Fig. 2.22: Vertical summit curve 141 Unit 3 Modern Field Survey Systems Fig. 3.1: Old version of a Geodimeter 171 Fig. 3.2: Measurement of (a) time, and (ii) phase difference 172 Fig. 3.3: Representation of phase shift 173 Fig. 3.4: An electromagnetic spectrum 174 Fig. 3.5: Reflecting prisms 175 Fig. 3.6: Total Station 177 Fig. 3.7: Components of a Total Station 177 Fig. 3.8: Parts of a Total Station 178 Fig. 3.9: Various steps of Total Station 179 Fig. 3.10: Keyboard and display unit 180 Fig. 3.11: Use of a reflectorless Total Station 181 Fig. 3.12: Robotic Total Station and prism with remote control unit 182 Fig. 3.13: Smart station (Total Station and GNSS combined) 183 Fig. 3.14: Depiction of various errors from Total Station 187 Fig. 3.15: The ellipsoidal height, orthometric height and geoid height 192 Fig. 3.16: Trilateration principle to compute receiver position 193 Fig. 3.17: Various segments of a GPS 193 xiv Fig. 3.18: The space segment 194 Fig. 3.19: The control segment 195 Fig. 3.20: The users segment 196 Fig. 3.21: L1 and L2 signals 196 Fig. 3.22: Determination of location from using trilateration method 203 Fig. 3.23: Static sessions lengths 205 Fig. 3.24: Real-time kinematic (RTK) surveys 207 Fig. 3.25: The concept of DGNSS survey 208 Fig. 3.26: Concept of WAAS GNSS survey 209 Fig. 3.27: Concept of MSAS survey 210 Fig. 3.28: Various accuracy levels using GPS 212 Fig. 3.29: Various sources of errors 213 Fig. 3.30: Depiction of multipath error 213 Fig. 3.31: Geometric dilution of precision 214 Fig. 3.32: Position dilution of precision 215 Fig. 3.33: A typical architecture of a GNSS tracker system 217 Unit 4 Photogrammetry Surveying Fig. 4.1: (Left) Nadar "elevating photography to the condition of art". (center) Nadar's earliest 225 surviving aerial image, taken above Paris in 1866. (right) Boston from a tethered balloon, 13th October, 1860. Fig. 4.2: Major phases of development of photogrammetry 226 Fig. 4.3: Vertical, low oblique and high oblique photographs 227 Fig. 4.4: Terrestrial or close-range photographs 228 Fig. 4.5: Aerial photograph and corresponding topographic map 230 Fig. 4.6: Route in flight planning 232 Fig. 4.7: Photography during a flight planning 232 Fig. 4.8: Geometry of an aerial photograph 234 Fig. 4.9: Fiducial marks on the photograph 235 Fig. 4.10: Representation of a titled photo 237 Fig. 4.11: Scale of a vertical photograph in a flat terrain 237 Fig. 4.12: Scale of a vertical photograph in an undulating terrain 238 Fig. 4.13: Relief displacement of a tower on a vertical photograph 239 Fig. 4.14: Stereoscopy (a) Human vision creating 3D, and (b) parallactic angle 241 Fig. 4.15: Stereoscopic exercise with index fingers 242 Fig. 4.16: (a) Lens stereoscope, and (b) line diagram of rays from lens stereoscope 243 Fig. 4.17: (a) Mirror stereoscope, and (b) line diagram rays of mirror stereoscope 244 Fig. 4.18: (a) Base lining of a stereo-pair, and (b) Creating a stereovision 245 Fig. 4.19: Parallax bar measurements 245 Fig. 4.20: Measurements on stereo-pair 246 Fig. 4.21: Parallax scale 246 Fig. 4.22: Height observations on a stereo-pair 247 Fig. 4.23: Geometry of a tilted photograph 249 Fig. 4.24: Tilt displacement 251 Fig. 4.25: Basic steps in aerial triangulation 253 Fig. 4.26: (a) Nine points on each photo, (b) Arundel method of radial line triangulation, and (c) 255 Rays to all points from the principal point Fig. 4.27: Scaling in Arundel’s method 256 Fig. 4.28: Bundle block adjustment 258 Fig. 4.29: Graphical representation of collinearity condition 259 Fig. 4.30: (a) six photographs, and (b) resultant mosaic 260 Fig. 4.31: Process involved to create a mosaic 261 Fig. 4.32 Buildings on (a) aerial photograph, and (b) orthophoto 262 Fig. 4.33: Creating a stereo-model in stereo-plotters 263 Fig. 4.34: An optical-mechanical projection instrument 263 xv Fig. 4.35: An analytical plotter 264 Fig. 4.36: Procedure used in analytical photogrammetry 264 Fig. 4.37: A digital workstation supported with photogrammetric software 265 Fig. 4.38: Processing of photos in a DPW 265 Unit 5 Remote Sensing Fig. 5.1: A complete passive remote sensing system 284 Fig. 5.2: Propagation of EMR 287 Fig. 5.3: Various part of the EMS 287 Fig. 5.4: Intensities of EMR at different wavelengths and temperatures 290 Fig. 5.5: Four types of interactions: transmission, reflection, scattering and absorption 290 Fig. 5.6: Types of scattering 291 Fig. 5.7: Atmospheric transmission process 293 Fig. 5.8: Spectral signature curves 293 Fig. 5.9: Field spectro-radiometer 294 Fig. 5.10: Sun-synchronous and Geosynchronous orbits 295 Fig. 5.11: Various platforms used in remote sensing 296 Fig. 5.12: Concept of IFOV and pixel 297 Fig. 5.13: Images at various spatial resolutions 298 Fig. 5.14: Landsat ETM images at different spectral bands 299 Fig. 5.15: Same image at different radiometric resolutions 300 Fig. 5.16: Temporal images to study the changes (A) QuickBird (May 2004), and (B) WorldView-2 300 (June, 2008) Fig. 5.17: Types of sensors 302 Fig. 5.18: Passive and active remote sensing sensors 303 Fig. 5.19: Remote sensing sensor systems 303 Fig. 5.20: Some thermal sensors 305 Fig. 5.21: Working principle of a RADAR 307 Fig. 5.22: LiDAR scanning 307 Fig. 5.23: Hyperion imaging spectrometer 308 Fig. 5.24: A view of Landsat-7 308 Fig. 5.25: Date-wise history of Landsats 310 Fig. 5.26: Landsat TM images, April 21, 2003, (a) band 1 (0.45-0.52 μm), (b) band 2 (0.52-0.60 310 μm), (c) band 3 (0.63-0.69 μm), (d) band 4 (0.76-0.90 μm), (e) band 5 (1.55-1.75 μm), (f) band 6 312 (10.40-12.50 μm), (g) band 7 (2.08-2.35 μm) Fig. 5.27: A view of SPOT-5 satellite Fig. 5.28: Rome as seen from SPOT-5 image 313 Fig. 5.29: SPOT-6 panchromatic image, August 2016 313 Fig. 5.30: Off-nadir capabilities of SPOT to collect images 314 Fig. 5.31: The IRS satellite 314 Fig. 5.32: The IRS-1B image of Himalaya and lower region 315 Fig. 5.33: (Left image) IRS-1D panchromatic image at 5.8 m resolution, and (right image) CARTOSAT-3 panchromatic image of Palm city area, Qatar, at 0.25 m resolution, dated 28-Dec- 2019 316 Fig. 5.34: (Left) IKONOS image of the Rio de Janeiro Port, Brasil, (middle) Quickbird image Houston Reliant Stadium, and (right) WorldView-2 image of downtown Oakland, California Fig. 5.35: (Left image) Multispectral images (Ose et al., 2016), and (Right image) False colour 318 composite from multispectral image Fig. 5.36: Fig. 5.36: (Left) True colour composite, and (Right) False color composite 321 Fig. 5.37: Hyperspectral remote sensing sensors and satellites Fig. 5.38: Pictorial representation of various visual interpretation elements 322 Fig. 5.39: Resampling methods 323 Fig. 5.40: Representation of an image 325 Fig. 5.41: Various shapes of histogram of an image 326 xvi Fig. 5.42: Original histogram and after linear contrast enhancement 327 Fig. 5.43: (Left) original satellite image, and (Right) after linear contrast enhancement 328 Fig. 5.44: Steps in supervised classification 329 Fig. 5.45: Broad steps involved in supervised classification and unsupervised classification 329 procedures 331 Fig. 5.46: ISODATA Clustering techniques, result after (left) first iteration, and (right) after 333 second iteration Fig. 5.47: (a) Supervised, and (b) unsupervised classification of SPOT 5 image of the area 333 Fig. 5.48: Error matrix or Confusion matrix 334 336 xvii  Contents Foreword (iv) Acknowledgement (v) Preface (vi) Outcome Based Education (vii) Course Outcomes (viii) Guidelines for Teachers (ix) Guidelines for Students (x) List of Abbreviations (xi) List of Figers (xiii) Unit 1: Surveying Unit specifics 1 Rationale 1 Pre-requisite 2 Unit outcomes 2 1.0 Introduction 2 1.1 Importance of Land Surveying 3 1.2 Basic Principles of Surveying 4 1.2.1 Working from whole to part 5 1.2.2 Establishing a point by at least two independent measurements 5 1.3 History of Mapping: Indian Perspective 6 1.4 Types of Surveying 8 1.4.1 Plane surveying 8 1.4.2 Geodetic surveying 8 1.5 Classification of Survey 8 1.5.1 Types of survey based on instruments 9 1.5.2 Types of survey based on purpose 9 1.6 Maps 13 1.7 Map Scale 13 1.8 Survey Stations 17 1.9 Survey Lines 18 1.10 Safety in Surveying 19 1.11 Units of Measurements 20 1.12 Various Errors in Measurements 21 1.13 Measurement of Distances 23 1.13.1 Measurement of distance by chain or tape 24 1.13.2 Ranging of survey lines 25 1.14 Measurement of Bearings 27 1.14.1 Types of bearings 27 1.14.2 Magnetic compasses 28 1.14.3 Fore bearing and back bearing 30 1.14.4 Magnetic declination 31 1.14.5 Local attraction 31 1.14.6 Computation of included angles from bearings 32 1.15 Measurement of Levels 34 1.15.1 Technical terms used in levelling 34 1.15.2 Levelling staff 36 1.15.3 Levels 37 1.15.4 Temporary adjustment of level 42 1.15.5 Redustion of levels 43 1.15.6 Types of direct levelling 44 1.15.7 Different types of errors 47 1.16 Contouring 50 xv  1.16.1 Contour interval 50 1.16.2 Factors deciding the contour interval 51 1.16.3 Characteristics of contour lines 51 1.16.4 Uses of a contour map 52 1.16.5 Methods of contouring 53 1.16.6 Digital elevation models 53 1.16.7 Area and volumes 54 1.17 Plane Tabling 59 1.17.1 Advantages and disadvantages of plane table surveying 59 1.17.2 Methods of plane tabling 59 1.18 Measurement of Angles by Theodolites 61 1.18.1 Various types of theodolites 61 1.18.2 Various parts of a Vernier theodolite 61 1.18.3 Technical terms 63 1.18.4 Measurement of horizontal angles 64 1.18.5 Measurement of vertical angles 66 1.18.6 Prolonging a straight line 67 1.18.7 Levelling with a theodolite 67 1.18.8 Traversing with a theodolite 68 1.18.9 Methods of theodolite traversing 68 1.18.10 Errors in theodolite observations 69 1.19 Tacheomtery 71 1.19.1 Instruments used 71 1.19.2 Methods of tacheometry 71 1.20 Trigonometrical Levelling 74 1.20.1 Finding height of an object which is accessible 74 1.20.2 Finding height of an object which is inaccessible 74 1.21 Traverse Computations 77 1.12.1 Adjustment of a closed traverse 77 1.12.2 Computation of coordinates 80 1.22 Triangulation Surveys 81 1.22.1 Trilateration 82 1.22.2 Principle of triangulation 82 1.22.3 Types of triangulations schemes 83 1.22.4 Technical terms 84 1.22.5 Triangulation survey work 87 1.22.6 Accuracy of triangulation 87 Unit summary 87 Numerical examples 87 Exercises for practice 106 References and suggested readings 109 Unit 2: Curves 111 Unit specifics 111 Rationale 111 Pre-requisite 111 Unit outcomes 111 2.1 Introduction 112 2.2 Classification of Horizontal Curves 112 2.2.1 Simple curves 112 2.2.2 Compound curves 112 2.2.3 Reverse curves 113 2.2.4 Transistion curves 113 2.3 Simple Circular Curves 113 2.3.1 Various parts of a curve 113 2.3.2 Designation of horizontal curves 114 xvi  2.3.3 Elements of a simple circular curve 115 2.3.4 Methods of curve setting 116 2.4 Compound Curves 126 2.4.1 Elements of a compound curve 126 2.4.2 Setting out the compound curve 127 2.5 Reverse Curves 128 2.5.1 Elements of a reverse curve 129 2.6 Transition Curves 130 2.6.1 Super-elevation or Cant 132 2.6.2 Length of a transition curve 133 2.6.3 Characteristics of a transition curve 134 2.7 Vertical Curves 136 2.7.1 Types of vertical curves 137 2.7.2 Elements of a vertical parabolic curve 139 2.7.3 Characteristics of a vertical curve 141 Unit summary 142 Solved Examples 142 Exercises for practice 163 References and suggested readings 167 Unit 3: Modern Field Survey Systems 169 Unit specifics 169 Rationale 169 Pre-requisite 169 Unit outcomes 169 3.1 Introduction 170 3.2 Electronic Distance Measurement (EDM) Devices 171 3.2.1 Principle of EDM 172 3.2.2 EDMs classification based on range 174 3.2.3 Reflecting prisms 175 3.2.4 Distance measurement 175 3.2.5 Errors in EDM measurements 176 3.3 Total Stations 176 3.3.1 Various components of a Total Station 177 3.3.2 Steps involved in Total Station surveying 178 3.3.3 Functions of Total Station 179 3.3.4 Reflectorless Total Stations 180 3.3.5 Robotic Total Stations 182 3.3.6 Smart Stations 183 3.3.7 Uses of Total Stations 183 3.3.8 Advantages and disadvantages of Total Stations 184 3.3.9 Calibration of Total Stations 184 3.3.10 Errors in Total Station measurements 185 3.4 Global Positioning Systems (GPS) 188 3.4.1 Technical terms in GNSS 189 3.4.2 Basic principle of GPS 192 3.4.3 Various segments of GPS 194 3.4.4 Signals of GNSS 197 3.4.5 Advantages and disadvantages of GNSS 200 3.4.6 Types of GNSS receivers 200 3.4.7 Working of a GNSS 202 3.4.8 GNSS surveying techniques 204 3.4.9 Other satellite based augmentation systems (SBAS) 208 3.4.10 Accuracy of GNSS observations 211 3.4.11 Errors in GNSS observations 212 3.4.12 Applications of GNSS technology 215 xvii Unit summary 219 Exercises for practice 219 References and suggested readings 220 Unit 4: Photogrammetry Surveying 223 Unit specifics 223 Rationale 223 Pre-requisite 223 Unit outcomes 223 4.1 Introduction 224 4.2 Historical Developments 225 4.3 Types of Aerial Photographs 227 4.4 Applications of Photogrammetry 228 4.5 Advantages and Disadvantages of Photogrammetry 229 4.6 Comparison of Aerial Photograph with Map 230 4.7 Flight Planning 231 4.8 Technical Terms in Aerial Photogrammetry 233 4.9 Scale of a Vertical Photograph 237 4.10 Relief Displacement of a Vertical Photograph 239 4.11 Stereoscopy 240 4.11.1 Stereoscopic model 242 4.11.2 Requirements of a stereoscopic vision 242 4.11.3 Stereoscopes 242 4.12 Determination of Height from Vertical Aerial Photographs 244 4.12.1 Orienting a stereo-pair of photographs 244 4.12.2 Measurements by Parallax Bar 245 4.12.3 Measurement of absolute parallax 246 4.12.4 Height determination 246 4.13 Tilted Photographs 248 4.13.1 Scale of a tilted photograph 248 4.13.2 Tilt displacement 250 4.14 Aerial Triangulation 253 4.14.1 Types of aerial triangulation 253 4.14.2 Orientation parameters 257 4.14.3 Bundle adjustment 258 4.15 Photogrammetric Mapping 259 4.15.1 Mosaics 260 4.15.2 Stereo-plotting instruments 262 4.15.3 Types of stereo-plotting instruments 263 4.15.4 Photgrammetric software 265 Unit summary 267 Solved examples 267 Exercises for practice 274 References and suggested readings 276 Unit 5: Remote Sensing 279 Unit specifics 279 Rationale 279 Pre-requisite 279 Unit outcomes 279 5.1 Introduction 280 5.2 Advantages and Disadvantages of Remote Sening Data 281 5.3 Applications of Remote Sensing 282 5.4 Components of a Passive Remote Sensing System 284 5.5 Technical Terms 284 5.6 Electromagnetic Spectrum (EMS) 286 xviii 5.7 Black Body Radiations 288 5.8 Interaction of EMR with Atmosphere 290 5.8.1 Types of interactions 291 5.8.2 Atmospheric windows 292 5.9 Spectral Signature of Objects 293 5.10 Types of Orbits 294 5.11 Types of Remote Sensing Platforms 296 5.12 Different Types of Resolutions 296 5.13 Different Types of Sensors 303 5.13.1 Based on the source of illumination 303 5.13.2 Based on internal geometry 304 5.13.3 Based on the wavelength 305 5.14 Some Remote Sensing Satellites and Sensors 309 5.15 Types of Remote Sensing Images 320 5.16 Visual Interpretation Methods 322 5.17 Digital Image Interpretation Methods 324 5.17.1 Image pre-processing 325 5.17.2 Image enhancement 327 5.17.3 Digital image classification 330 5.17.4 Accuracy assessment 335 Unit summary 337 Exercises for practice 338 References and suggested readings 340 CO and PO Attainment Table 344 Index 345 xix  UNIT-1 Surveying Unit Specifics Through this unit we have discussed the following aspects:  Principle of Surveying and historical background  Various types of surveying  Various maps and their characteristics  Linear, angular and graphical methods of surveying and their utility  Types of levels, including auto levels and digital levels, and their salient features  Levelling observation methods  Contour mapping and utility  Magnetic bearing and compasses  Measurements of magnetic bearing  Various types of theodolites and their salient features  Theodolite observation methods for taking horizontal and vertical angles  Plane table survey  Traverse, Triangulation and Trilateration  Traversing with theodolites  Error adjustments  Types of triangulations and associated processes  Numerical problems In addition to the basic principle of surveying, the working of levels, compass and theodolites has been explained. The practical utility of these surveying equipment is presented for field data collection required for creating maps, as well as making these observations error free. Once the data is collected and corrected, topographic maps can be created by plane table survey methods in the field. Thenatic maps may be created from high resolution images, cutting down the requirements of large manpower and funds. Questions of short and long answer types are given following lower and higher order of Bloom’s taxonomy, and a list of references and suggested readings is given in the unit so that the students can go through them for acquiring additional in-depth knowledge. Rationale This unit provides details of various types of surveying, maps, levels, compass and theodolites. Each of these equipments are used for a specific purpose of data collection required for creating maps. It explains various components of level, compass, plane table, and theodolite. Working of these equipments using various methods has been explained so that the students make use of these equipment in the field. Various methods used in the field and errors associated are also given. In levelling, angular observations, and traversing, errors and their minimisation are also discussed so that the users can minimise the errors from the field data. The computed coordinates of the surveyed points provide good 1 horizontal and vertical control for civil engineering projects. Plane table survey will further enhance the understanding of map making processes. Pre-Requisite Mathematics: geometry and trigonometry, Earth surface. Unit Outcomes List of outcomes of this unit is as follows: U1-O1: Describe various types of Land survey, Maps, Levels, Compasses, and Theodolites U1-O2: Explain the essential components and characteristics of Maps, Levels, Compasses, and Theodolites U1-O3: Realize the role of Maps, Levels, Compasses, and Theodolites for field data collection U1-O4: Describe various methods of data collection using, Levels, Compasses, and Theodolites, and apply corrections to observations U1-O5: Apply the parameters collected in the field for providing horizontal and vertical controls, and creating the maps. Unit-1 Expected Mapping with Programme Outcomes Outcomes (1- Weak correlation; 2- Medium correlation; 3- Strong correlation) CO-1 CO-2 CO-3 CO-4 CO-5 CO-6 U1-O1 2 2 3 2 1 2 U1-O2 3 1 2 1 2 - U1-O3 2 3 2 3 - 3 U1-O4 2 2 3 2 2 - U1-O5 2 3 2 1 - 2 1.0 Introduction Surveying is a core subject of civil engineering and it has an important role to play. It is the starting point of many projects, such as roads and railways, buildings, bridges, pipelines, transmission lines, dams, and many more (Schofield, 1984). Surveying is “the technique of accurately determining the relative position of natural and man-made features above or below the surface of the Earth, by means of direct or indirect elevation, distance and angular measurements”. According to the American Congress on Surveying and Mapping (ACSM), ‘Surveying is the science and art of making all essential measurements to determine the relative position of points or physical and cultural details above, on, or beneath the surface of the Earth, and to depict them in a usable form, or to establish the position of points or details’. Surveying is a means of making accurate measurements of the Earth’s surfaces, including the interpretation of data so as to make it usable, and establishment of relative position and size (Survey Manual, 2014). It involves largely the field work which is done to capture and storage of field data using instruments and techniques specific for the type of survey work. Surveying also includes the technique of establishing the points by pre-determined angular 2 and linear measurements. Thus, surveying has two distinct functions: (i) to determine the relative horizontal and vertical positions of the objects/features for the process of mapping, and (ii) to demarcate the land boundaries, establish the points to exactly layout the project on the ground, and control the construction work of a project. The word 'Map’ originates from the Latin word 'mappa', means a tablecloth or napkin where 3-dimensional Earth features are represented on 2-dimensional cloth or paper. A map represents the 2D projection of the 3D terrain surveyed, which could be utilised to draw plans and sections to compute the area of land, or volume of a land mass or layout of an engineering structure. In land surveying, data are collected by using field surveying equipment and represented graphically on a piece of paper, called 'Map'. As the surveying technology grew, advanced materials, electronics, sensors and software are introduced in data collection, and analysis (Garg, 2021). These measurements may be used for the representation of different features in different forms. These features/details may be represented in analogue form as a topographic map with contours, plan or chart, or in digital form, such as a Digital Terrain Model (DTM). As surveying allows us to acquire data on the relative positions, horizontal distances, and elevations of points, the objectives of surveying can be stated as follows (Schofiled, 1984; Basak, 2017): 1. Collect and record data about the relative positions of points/objects on the surface of the Earth. 2. Establish horizontal and vertical controls required for accurate mapping and subsequently for construction. 3. Prepare maps required for various civil engineering projects. 4. Compute areas and volumes of earthwork, required in various projects. 5. Layout of various engineering works on the ground using survey data. 1.1 Importance of Land Surveying Ever since the mankind acquired the sense of possessing the land and property, the art of surveying and mapping came into existence (Survey Manual, 2014). In the early days, the demarcation of land and defining the boundaries were extremely difficult tasks, and done as rough representation using conventional devices. With the growth of knowledge, skill and technology, development of surveying instruments and techniques of data collection and analysis improved considerably. Today, surveying is of vital importance as accurate planning and design of all civil engineering projects (Garg, 2021), such as railways, highways, tunneling, irrigation canal, dams, reservoirs, sewerage works, airports, seaports, building complex, etc. are based upon the quality of surveying measurements. The knowledge of surveying is advantageous in many phases of civil engineering. The first task in surveying is to prepare a detailed topographical map of the area, and then either draw the sections of the best possible alignment, or compute the amount of earthwork or plan the structures on the map, depending upon the nature of the project (Chandra, 2007). The geographic and economic feasibility of the engineering project cannot be properly ascertained without undertaking a detailed survey work. Thus, the knowledge of surveying is fundamental and very useful to civil engineering professionals. 3 Surveying helps demarcating the land boundaries accurately on the ground. Surveying is essential to fix the national and state boundaries, map rivers and lakes, prepare maps of coastlines, etc. It is important to know the exact shape and size of the land boundary for acquisition of land or paying compensation to the land owners, and planning the construction. Many land properties have noticeable problems, mainly due to improper surveys, miscalculations in past surveys, titles of the land, error in measurements, etc. Also many land properties are created from multiple divisions of a larger piece of land over the years; and with every additional division, the risk of miscalculation/error in demarcation increases. The dispute in land measurements may lead to court cases to decide about the land ownerships. Many such problem can thus be detected on time through proper survey, and actions are taken on the basis of facts and figures provided by surveying measurements. Surveying is also important in archaeology, geology, geophysics, landscape architecture, astronomy, meteorology, and seismology, including military engineering. Civil engineers must know the accuracy achieved in design and layout processes, as well as in construction. In addition to understanding the limits of accuracy, surveyors and engineers must know at what precision field data is to be collected to justify the accuracy. In particular, civil engineers must have a thorough understanding of the methods and instruments used, including their capabilities and limitations. This knowledge is best obtained by making observations with the kinds of modern equipment generally used in practice. Civil engineers play an integral role in land development from planning and designing to the final construction of roads, buildings, bridges, dams, canals, stadium, buildings and utilities, and subsequently their maintenance and/or upgradation. The first and foremost requirement therefore is to have an accurate mapping of the land, as surveyors are the first to work at any construction site. For example, in a multipurpose building project (smart city), designing the project, planning the structures accurately and safely, and ensuring the buildings to be constructed as per specifications; all are the responsibilities of civil engineers. Since surveying measurements are used for providing horizontal and vertical controls on the ground, these are required not only for layout of structure accurately on the ground for construction purpose, but also useful to control the accuracy of entire construction of the structures (Duggal, 2004). These controls can also be used to make the actual estimate of the construction of structures while making payment to the contractor. The role of surveying as a professional activity is expanding to include other techniques and skills, under one umbrella, known as Geospatial technology. The surveying professional are slowly adapting the modern approaches of data collection, data analysis and mapping in digital environment. These surveying approaches require a good working knowledge of photogrammetry, remote sensing, laser scanners, Global Positioning Systems (GPS), Unmanned Aerial Vehicles (UAVs), computer cartography, Geographical Information Systems (GIS), and associated software to analyse the data, generate detailed maps, visualize the terrain from satellite images, or integrate multiple geo-referenced databases (Garg, 2019). 4 1.2 Basic Principles of Surveying There are two basic principles of surveying which are to be followed for accurate and systematic survey measurements on the Earth surface. These are given below. 1.2.1 Working from whole to part This is a fundamental and most important principle of surveying. Almost all survey works are required to follow this principle, particularly larger (whole) areas. In working from whole to part, a large (whole) area is divided into smaller parts by providing horizontal controls throughout the area. The smallest part of the area will consist of a triangle. If surveying is done without dividing into smaller parts, any error occurred in a part gets magnified at the end of entire survey work, and the error becomes large which can’t be accepted for a good work. Whereas, on the other hand, any error occurred in smaller parts (triangle) is adjusted independently, and at the end of survey no error is left. Thus, the basic objective of this principle is to adjust the error locally within each small figure (triangle) independently and preventing the accumulation of errors. In India, for large area survey works, Survey of India (SoI), Dehradun, established the control points very accurately at large distances by using triangulation method. From these control points, smaller areas are surveyed by setting out a network of triangles. Such sub- division continues with reference to the previously established systems of points, till all the details are surveyed. Figure 1.1 First principle of surveying: working from whole to part 1.2.2 Establishing a point by at least two independent measurements Horizontal control points in surveying are located by linear and/or angular measurements. If two control points are established by surveying measurements, a new point (third point) can be established with the help of these two known control points by taking two linear or two angular measurements, or by one linear and one angular measurement. In other words, indirectly the location of the new point is established using the geometry or trigonometry of the triangle formed by these three points. In Figure 1.2a, let P and Q be two control points, and a new point R is to be established by means of observations from points P and Q. Point R can be established using the distances PR, and R’R. In Fig. 1.2(b), R is established using the distances PR and QR. In Fig. 1.2(c), R is established by the angle RPQ and distances PR or by establishing angle RPQ and distance QR. In Fig. 1.2(d), R is established using the angles PQR and QPR. R R 5 P  Q P Q R’ (a) (b) R R αα ꞵ P Q Q P (c) (d) Figure 1.2 Second principle of surveying 1.3 History of Mapping: Indian Perspective As early as 1400 BCE, evidence of some form of boundary surveying has been found in the fertile valleys and plains of the Tigris, Euphrates, and Nile rivers. In India, evidence of map making skills has been found in the Brahmand Purana as far back as the 5th century (Chadha, 1991). Knowledge of land was presented in graphical form which described the extent and shape of territories. The art of surveying and techniques of mensuration of areas are described in Sulva Sutra (science of mensuration) and in the Arth Shastra of Chanakya, written in the 3rd century BC. In the 5th century, Aryabhatta, who wrote Surya Siddhant, calculated the Earth's circumference to be 25,080 miles- less than 200 miles off modern measurements of the equator (Phillimore, 1945). Official surveying and mapping has been in practice in India, since way back 16th century. Raja Todar Mal during Akbar’s and Sher Shah Suri regime introduced agriculture land measurements, termed as cadastral survey, which was done with foot and iron chains (Satyaprakash, 2010). Drawing used to be prepared cartographically with free-hand and scales. In India, the revenue maps were earlier prepared on a piece of cloth, called 'Khasra’ maps. These maps were earlier prepared by a method of distance measurement, known as pacing, which gave an idea of boundary and dimensions of land and property. Later, iron chains of 20 ft and 30 ft long were used to improve the distance measurement accuracy. Khasra maps and chains are used even today by many Patwaris and Village Development Officers for demarcation of property and collection of revenue. The Indian terrain was completely mapped by the painstaking efforts of distinguished surveyors, such as Mr. Lambton and Sir George Everest (Phillimore, 1945). The angle- measuring instruments, called Theodolites, were developed to study the astronomy that were based on arcs of large radii, making such instruments too large for field use. The 36 inch theodolite used in the Indian triangulation is shown in Figure 1.3. A 16 inch diameter Transit Theodolite with magnifiers, which has been used for measuring horizontal and vertical angles for the alignment, layout and construction of Ganga Canal, was designed and manufactured by the Canal Foundry (now known as Canal Workshop), Roorkee. (Late) Prof. H. Williams in 1937 carried out modifications in the Theodolite 6 which was used for teaching and training to Engineers as well as for taking observations. Surveyor Compass with 10 least count was developed and manufactured at Roorkee to find out the bearing and direction required for the construction of Ganga Canal. In this Compass, numerals have been shown in English as well as Arbi languages. Figure 1.3 The 36 inch theodolite used in the Indian triangulation (Keay, 1983) The East India Company, after the Agra famine in 1937-38 where about one million people died, felt the need to build an irrigation system in the Doab region (Meerut to Allahabad zone) with support from skilled hands. Colonel Cautley was given the charge of constructing the Ganga canal. He suggested to James Thomason, the then Lieutenant- Governor of the North-West provinces, about the need to train locals in civil engineering for completing their ongoing projects. The students were to be trained systematically in surveying, leveling and drawing with proper infrastructure. This led to the foundation of the country’s first-ever engineering college at Roorkee on September 23, 1847. The Survey of India (SoI), under the Department of Science & Technology, is the oldest scientific department of the Govt. of India, which was set up in 1767 to help consolidate the territories of the British East India Company (Chadha, 1991). The SoI is the principal mapping agency of the country. The great trigonometric series spanning the country from north to south and east to west are some of the best geodetic control series available in the world. The foremost topographical survey in the south was the one carried out by Colin Mackenzie in Kanara and Mysore. The SoI is fully equipped with digital devices and software to ensure that the country's domain is explored and mapped suitably using the latest technology. It has oriented the technology to meet the needs of defense forces, planners and scientists in the field of geo-sciences, land and resource management, and many scientific programs of the country. From the 19th century, the use of trigonometric method marked a historic moment in the process of surveying. This was the first time that a purely geometric method was utilised for making geographical calculations. The method of measurement through triangulation was conceived by the EIC officer William Lambdon and later under his successor George 7 Everest, which became the responsibility of the SoI. One of the greatest accomplishments of the trigonometric survey was the measurement of Mount Everest, K2 and Kanchenjunga. As human brain is always engaged in development of new procedures to overcome the shortcomings, a rapid growth has taken place since then. Digital maps became the authentic tools to claim the ownership. Over the past, several changes have occurred in surveying and mapping field, resulting in the techniques today which are fully automated and software based from data collection to analysis to mapping. 1.4 Types of Surveying The two broad types of land survey used are plane surveying and geodetic surveying, depending upon whether the spherical shape of the Earth is taken into account or not (Punmia et al., 2016). These are briefly described below. 1.4.1 Plane surveying In plane surveying, the Earth surface is considered as a plane surface, and its spheroidal shape is neglected. For small projects covering area less than 250 sq.km, Earth curvature is not accounted for distance measurements. The line joining any two stations is considered to be straight, and three points will make a plain triangle. Surveys for engineering projects fall under this category. Plane surveying uses normal instruments, like measuring tape, theodolite, level, etc., and the survey accuracy is low. 1.4.2 Geodetic surveying This type of surveying takes into account the true shape of the Earth. Earth curvature correction is applied to the observations. The triangle formed by any three points is considered as spherical. Geodetic surveys are carried out for areas greater than 250 sq.km. For large areas, degree of accuracy of measurements is high, and therefore geodetic survey requires sophisticated and high precision equipment, like the GPS, Total Station. Geodetic survey is used to provide control points to which small surveys can be connected. 1.5 Classification of Survey Surveys can be further classified into several categories depending on the purpose, instruments, techniques used, etc. These classifications are shown in Table 1.1. Table 1.1 Classification of surveys based on Instruments Place Methods Purpose Chain or tape Land Levelling Topographic Level Water Trigonometrical levelling Geodetic Theodolite Underground Traversing Engineering Compass Aerial Tachometry Route Tachometer Triangulation Cadastral EDM Trilateration City Total Station Mine Plane Table Geology GPS Underground utility GPR Hydrographic Laser scanners Aerial 8  Satellite UAV/Drone 1.5.1 Types of survey based on instruments Earlier, measurements of distances and directions were mainly used to prepare maps of the area, and surveys were classified based upon the instruments used. Chains, tapes, levels, magnetic compasses, and theodolites were popularly used, either single or in combination with other equipment. With the advancement in electronics and digital technology, many modern instruments are now available for data collection and mapping, which are capable to collect the data alone, and no other instrument is generally required, for example Total station, Laser scanners and GPS. Figure 1.4 shows the images of some of these equipment. (a) Chains In chain survey, a metallic chain is used to measure the linear distances. The chain traversing is done by dividing the small area to be surveyed into a number of triangles. Using the sides of the triangles by chain surveying, other details are worked out. Chains meant for survey work are available in length of 20 or 30 m. Later, chains due to their inaccuracy, difficulty to use, and wear & tear in the field, were replaced by the tapes. In addition, many corrections are applied while making the long distance measurements with chain. (b) Tapes Many different varieties of measuring tapes are available, with different materials, lengths and designs. The most common type of tape is made of fibre glass reinforced plastic tapes and those with stainless steel. Steel tapes stretch very little, and are little expensive but gets kinks easily if not handled properly. Steel tapes also get rust very quickly. Measurements over 30 m are not recommended as that length of tape is difficult to manage and the sag in the tape makes the measurements inaccurate. (c) Levels A level instrument is used to find the difference in elevation between the points. It is used along with a graduated rod, known as the leveling staff. If we link the observations to a known point, the elevation of other unknown points can be determined. (d) Theodolites A theodolite is used to measure horizontal and vertical angles. Theodolites are frequently used to carry out traversing where angles and distances are measured simultaneously. These angle are required to establish horizontal and vertical controls in the area. Theodolites can also be used for prolongation of a line, alignment work, and levelling work. (e) Compass A magnetic compass works on the principle that a freely suspended needle points in the magnetic north-south direction (reference direction). This instrument gives the direction of a line with respect to reference direction. A compass, together with a chain or tape or Total Station, can be used to survey a given area using methods, such as traversing. 9 (f) Techeometer A tacheometer is similar to a theodolite but has an anallactic lens and a stadia diaphragm having three horizontal hairs. The readings taken on a levelling staff against all the three cross hairs enable the horizontal distances to be computed. The central wire reading is linked to some Bench Mark (BM) to determine the elevation. (g) EDM The Electronic Distance Measuring (EDM) device measures the slope distance between EDM instrument and a prism (reflector). The EDM generates infrared (IR) or microwave which travels through the atmosphere and strikes the reflector kept at an unknown point. The instrument measures the travel time of return beam, and computes the distance (distance= velocity x time). The phase difference between the instrument station and the reflector station is also used to compute the slope distance. For details of EDM refer to Unit-3. (a) Chain (b) Tape (c) Level and Staff (d) Theodolite (e) Compass (g) EDM (j) GNSS (h) Total (i) Plane Table Station (l) Laser Scanner k) GPR (m) UAV/Drone 10  (n) Aerial (o) Satellite Photograph Image Figure 1.4 Surveying based on equipment and tools (h) Total Station A total station is a combination of an electronic theodolite and an EDM. Horizontal distances and horizontal & vertical angles are determined using a total station. Total station equipment is used all forms of surveys requiring a very high level of precession. A total station can display and store the field data, and transfer the data to a computer for further processing. For details of Total Stations refer to Unit-3. (i) Plane Table A plane table is like a drawing board, which is used in the field to prepare a map of the area at desired scale. In plane table survey, fieldwork and plotting work proceed simultaneously. It is used along with an alidade which provides the direction towards the object to be plotted, and with a chain or tape, and tacheometer or a Total Station to measure the distance and elevation of the objects/features. (j) GNSS The Global Navigation Satellite System (GNSS) device (receiver) is very useful in surveying and mapping. Depending on the type of receiver, it shall receive signals from the various GNSS constellations such as Global Positioning System (GPS), GLONASS, GALILEO satellites and provides 3D coordinates of the point on the Earth surface, anytime, where observations have been taken (Garg, 2019). These 3D coordinates can be used in software to process and generate a map as well creation of digital elevation model (DEM). For details of GNSS refer to Unit-3. (k) GPR The Ground Penetrating Radar (GPR) device emits radar beams that penetrate into the ground to a certain depth, depending on the wavelength and frequency of antenna of radar beam (Garg, 2021). It will display the return signals from the objects which are below the Earth surface. Any underground utility, buried structures & objects, ground water table, etc., can be mapped with the GPR. Mapping all the underground utility is necessary in all modern townships, including smart cities. For details of GPS refer to Garg (2021). (l) Laser Scanners Laser scanners emit laser beams that strike to the objects and return back to the instrument. The instrument provides 3D coordinates of the objects which could be used to generate the DEM of the area (Garg, 2021). There are two types of laser scanners; terrestrial (ground based) and aerial laser scanners, and depending on the use, 3D models and maps or profiles can be generated for the area. For details of Laser Scanners refer to Garg (2021). 11 (m) UAVs/Drones The Unmanned Aerial Vehicle (UAV) or drone are low flying aircrafts used for collecting very high-resolution images of laser point cloud data (Garg, 2020). These data are very helpful to generate DEM of the area. Today, UAVs have large number of applications in mapping, monitoring and management of civil engineering and other projects. For details of UAVs/Drones refer to Garg (2020). (n) Aircrafts In aerial photogrammetry, aerial photographs are acquired and used for preparation of various thematic maps at different scales. Manual photogrammetric techniques require simple equipment, such as stereoscopes, parallax bar, analytical plotting devices, whereas the digital photogrammetric methods require sophisticated devices (workstations) and photogrammetric software to create various kind of maps (Garg, 2019). For details of photogrammetry refer to Unit-4. (o) Remote Sensing Satellites Large number of satellite images are available from various satellites, which can be processed through image processing software or in GIS environment to generate maps at different scales (Garg, 2019). Using different time images in GIS, a change scenario can be generated which is very helpful in planning, designing and monitoring various civil engineering projects. In addition, GIS can be used to make a query form the exhaustive database which otherwise is not possible. For details of remote sensing refer to Unit-5. 1.5.2 Types of survey based on purpose (a) Control surveys These are carried out to establish a network of horizontal and vertical controls that serve as a reference framework for completing the survey work with desired accuracy. Many control surveys performed today are done using Total Station and GPS instruments. (b) Topographic surveys They are carried out to determine the locations of natural and man-made features, and their elevations and representation on a map. (c) Land boundary and cadastral surveys These are used to establish property lines and corners of the property. The term cadastral is applied to surveys of the public lands systems. (d) Hydrographic surveys They are used to define shorelines and depths of lakes, streams, oceans, reservoirs, and other bodies of water. (e) Alignment surveys These are conducted to plan, design, and construct highways, railroads, pipelines, and other linear projects. 12 (f) Construction surveys They provide line, grade, control elevations, horizontal positions, dimensions, and configurations for construction operations. They are also used for computing the bill and quantities of construction. (g) Mine surveys These are performed above and below the ground to guide tunnelling and other operations associated with mining. These surveys are carried out for mineral and energy resource exploration. 1.6 Maps One of the basic objectives of surveying is to finally prepare various types of maps useful for engineering works (Survey Manual, 2014). Maps are graphical representation of Earth surface features to some scale. Two broad types of maps; planimetric and topographic, are prepared as a result of surveys. The former, called plan map, depicts the natural and cultural features in their plan (x-y) views only, while the latter includes planimetric features, and the elevation (z) of ground surface. The topography represents the shape, configuration, relief, slope, roughness, or three-dimensional characteristics of the Earth's surface. Both types of maps are used by a larger community, such as engineers and planners to determine the most desirable and economical locations of projects, such as highways, rails, roads, canals, pipelines, transmission lines, reservoirs, and other facilities; by architects in housing and landscape design; by geologists to investigate the mineral, oil, water, stable slopes, and other resources; by foresters to locate wildlife, forest fire-control routes, identifying new sites for plantations; and by archeologists, geographers, and scientists in numerous fields. Maps depict the locations as well a relief of natural and cultural features on the Earth's surface (Garg, 2021). Natural features normally shown on maps include forests, vegetation, rivers, lakes, snow, oceans, etc., while cultural features are the man-made features and include roads, rails, buildings, bridges, tower, canal etc. Traditionally, engineering maps have been prepared using manual drafting methods and plane table survey. With the availability of digital data from total station, GPS, laser scanners and digital images form photogrammetry and remote sensing, now the majority of maps are produced using computers, computer-aided drafting (CAD), and GIS software. The natural and cultural features on the maps are depicted graphically by points, lines and polygons, with different symbols and colours. For example, the relief of the Earth includes its hills, valleys, plains, slopes and other surface irregularities, which are represented in the form of contour lines. A map will also have the names of places, rivers and legends to identify the different objects. The standard symbols and colours used for various natural and man-made objects, are shown in Table 1.2. For example, contours as burnt sienna, buildings as light red, water as persian blue, trees and vegetation as green, agricultural land as yellow, etc. 1.7 Map Scale 13 The distance between any two points on a map, measured along a straight line, is called the map distance, while the distance between the same two places on the ground, measured along a straight line, is called the ground distance. The ratio between the map distance and the ground distance is called the scale of map. Map scales are represented in three ways; (i) by ratio or representative fraction (RF) or ratio, such as 1:1200 or 1/1200, (ii) by an equivalence, for example, l in.= 100 ft. (1200 in.), and (iii) graphically using a linear scale. In defining scale by ratio or RF, same units are used for map distance and corresponding object distance, and thus 1:1200 could mean 1 unit on the map is equivalent to 1200 unit on the ground. An equivalence scale of 1 inch= l00 ft. indicates that 1 inch on the map is equivalent to 100 ft. or 1200 in. on the ground. It is possible to convert from a ratio to an equivalence scale and vise-versa. As an example, 1 inch= 100 ft. is converted to a RF by multiplying 100 ft by 12 which converts it to inches and gives a ratio of 1:1200. Table 1.2 Colours and symbols of various features on topographic maps (https://geokult.com/2011/09/14/map-symbolisation/) 14 A linear scale is useful to measure the distance directly from the map. It allows an accurate measurement on the map, as direct measurement on a paper map using numerical scale may not be very accurate due to little contraction or expansion of paper with the climatic conditions. But a linear scale drawn on a map will yield correct result, even after enlargement or reduction of a map. In the graphic or linear scale, map distance is shown using a straight line. The length of the line of a linear scale depends on the size of the map, but is usually between 12 cm and 20 cm that is divided into parts known as primary divisions. The primary units to the left of zero must be exactly the same size or length as the primary units to the right of zero. The first primary division on the left is further sub- divided into smaller parts known as secondary divisions. The starting or zero point of the linear scale should be after the first primary division from the left. The primary divisions are to the right of zero, while the secondary divisions are to the left of zero. The example in Figure 1.5 shows a linear scale where 1 cm on the map equals to 1 km on the ground. Secondary divisions are divided into five equal parts (it may also be divided into 10), and each part represents 200 m on the ground. Thus, the ground distance can be computed using linear scale by measuring that distance on map Figure 1.5 A typical linear scale The Survey of India prepares various maps based on actual survey of land for the whole country. These maps which show the details about landforms, drainage patterns, land use, settlement patterns, transport, forest and cultural features. The topographical maps or topo sheets, prepared by Survey of India, are available at three scales; 1: 25,000, 1: 50,000 and 1: 2,50,000. The topographical maps also show a network of parallels (lines of Latitudes