Modern surveying techniques
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Modern surveying techniques utilizes advanced electronic equipment for measuring distances, angles, and elevations. This includes digital levels that use electronic image processing of barcoded staff readings, total stations that integrate distance and angle measurements, and electromagnetic distance measurement instruments. Remote sensing involves analyzing sensor data such as satellite imagery to obtain information about areas without direct contact. It has various applications including agriculture, urban planning, hydrology, and disaster management by aiding tasks such as early warning, damage assessment, and recovery efforts.
Modern surveying techniques
- 1. MODERN SURVEYING TECHNIQUES Sunil Kumar(111581) Sunny Jaiswal(111582)
- 2. CONTENT 1. Basics of surveying 2. Modern surveying equipments 3. Remote sensing
- 3. BASICS OF THE SURVEYING • Surveying is defined as the science of making measurements especially of the earth surface. This is being done by finding out the spatial location(relative/absolute) of points on or near the earth surface. • Different method and instrument are being used to facilitate the work of surveying.
- 4. OBJECTIVE OF SURVEYING 1. To collect field data. 2. To prepare plan or map of the area surveyed. 3. To analyze and calculate the field parameters for setting out operation of acctual engineering works . 4. To set out the field parameters at the site for further engineering works.
- 5. MODERN SURVEYING EQUIPMENT • Revolutionary changes have taken place in last few years in surveying instruments that are used for measuring level differences, distances and angles. • This has become possible because of introduction of electronics in these measurements. With rapid advancements in the technology and availability of cheaper and innovative electronic components, these instruments have become affordable and easy to use.
- 6. DIGITAL LEVEL • Recently electronic digital levels have evolved as a result of development in electronics and digital image processing. • Digital levels use electronic image processing to evaluate the special bar-coded staff reading. • This bar-coded pattern is converted into elevation and distance values using a digital image matching procedure within the instrument.
- 7. SALIENT FEATURES OF DIGITAL LEVEL • Fatigue-free observation as visual staff reading by the observer is not required. • User friendly menus with easy to read, digital display of results. • Measurement of consistent precision and reliability due to automation. • Automatic data storage eliminates booking and its associated errors.
- 8. • Fast, economic surveys resulting in saving in time (up to 50% less effort has been claimed by manufacturers). • Data on the storage medium of the level can be downloaded to a computer enabling quick data reduction for various purposes.
- 9. COMPONENTS OF DIGITAL LEVEL • The following discussion on digital levels has been primarily taken from Schoffield (2002). • Main components of digital level consist of two parts: Hardware (Digital level and levelling staff) and Software. • Both digital level and associated staff are manufactured so that they can be used for both conventional and digital operations.
- 10. • Typically digital level has the same optical and mechanical components as a normal automatic level. • However, for the purpose of electronic staff reading a beam splitter is incorporated which transfers the bar code image to a detector diode array. • The light, reflected from the white elements only of the bar code, is divided into infrared and visible light components by the beam splitter.
- 11. • The visible light passes on to the observer, the infrared to diode array. • The acquired bar code image is converted into an analogous video signal, which is then compared with a stored reference code within the instrument.
- 12. • Various capabilities of digital levels are as follows: 1. measuring elevation. 2. measuring height difference. 3. measuring height difference with multiple instrument positions. 4. levelling 6. setting out with horizontal distance 7. levelling of ceilings
- 14. PRINCIPLE OF EDMI • The general principle involves sending a modulated Electro-magnetic (EM) beam from one transmitter at the master station to a reflector at the remote station and receiving it back at the master station. • The instrument measures slope distance between transmitter and receiver by modulating the continuous carrier wave at different frequencies, and then measuring the phase difference at the master station between the outgoing and the incoming signals. This establishes the following relationship for a double distance (2D):
- 16. • The following photographs show different types of EDMIs.
- 17. OPERATION WITH EDMI • Measurement with EDMI involves four basic steps: (a) Set up (b) Aim (c) Measure (d) Record • Setting up: The instrument is centered over a station by means of tribrach. Reflector prisms are set over the remote station on tribrach.
- 18. • Aiming: The instrument is aimed at prisms by using sighting devices or theodolite telescope. Slow motion screws are used to intersect the prism centre. Some kind of electronic sound or beeping signal helps the user to indicate the status of centering. • Measurement: The operator presses the measure button to record the slope distance which is displayed on LCD panel. • Recording: The information on LCD panel can be recorded manually or automatically. All meteorological parameters are also recorded.
- 19. ERROR IN MEASUREMENT WITH EDMI 1. Instrument errors : • centering at the master and slave station. • pointing/sighting of reflector. • entry of correct values of prevailing atmospheric conditions.
- 20. 2. Atmospheric errors : Meteorological conditions (temperature, pressure, humidity, etc.) have to be taken into account to correct for the systematic error arising due to this. These errors can be removed by applying an appropriate atmospheric correction model that takes care of different meteorological parameters from the standard one. 3. Instrumental error : Consists of three components - scale error, zero error and cyclic error. These are systematic in nature
- 21. TOTAL STATION • These instruments can record horizontal and vertical angles together with slope distance and can be considered as combined EDM plus electronic theodolite. • The microprocessor in TS can perform various mathematical operations such as averaging, multiple angle and distance measurements, horizontal and vertical distances, X, Y, Z coordinates, distance between observed points and corrections for atmospheric and instrumental corrections.
- 22. • Due to the versatility and the lower cost of electronic components, future field instruments will be more like total stations that measure angle and distance simultaneously having: all capabilities of theodolites electronic recording of horizontal and vertical angles storage capabilities of all relevant measurements (spatial and non-spatial attribute data) for manipulation with computer.
- 23. SALIENT FEATURES OF TS • TS is a fully integrated equipment that captures all the spatial data necessary for a three-dimensional position fix. • The angles and distances are displayed on a digital readout and can be recorded at the press of a button. Various components of a typical TS are shown in Figure:
- 25. STORAGE • Most TS have on-board storage of records using PCMCIA memory cards of different capacity. The card memory unit can be connected to any external computer or to a special card reader for data transfer. • The observations can also be downloaded directly into intelligent electronic data loggers. Both systems can be used in reverse to load information into the instruments. • Some instruments and/or data loggers can be interfaced directly with a computer for immediate processing and plotting of the data (Kavanagh, 2003).
- 27. FIELD OPERATION WITH TS • Various field operations in TS are in the form of wide variety of programs integrated with microprocessor and implemented with the help of data collector. • All these programs need that the instrument station and at least one reference station be identified so that all subsequent stations can be identified in terms of (X, Y, Z). Typical programs include the following functions:
- 28. • • • • • • • • Point location Missing line measurement (MLM) Resection Remote distance and elevation measurement Offset measurements Layout or setting out operation Area computation For details on above functions, one can refer to the user manual of any TS.
- 29. Different Types of TS and accessories • Trimble(5600IR)
- 32. REMOTE SENSING • Science and art of obtaining information about an object, area, or phenomenon through the analysis of data acquired by a device that is not in contact with the object, area, or phenomenon under investigation
- 33. REMOTE SENSING SYESTEM • A typical remote sensing system consists of the following sub-systems: (a) scene (b) sensor (c) processing (ground) segment • Various stages in these sub-systems are indicated in the next figure. • The electro-magnetic (EM) energy forms the fundamental component of a RS system
- 35. • The following steps indicate how remotely sensed data gets converted into useful information: 1. Source of EM energy (sun/self emission: transmitter onboard sensor). 2. Transmission of energy from the source to the surface of the earth and its interaction with the atmosphere (absorption/scattering). 3. Interaction of EMR with the earth surface (reflection, absorption, transmission) or reemission/self emission. 4. Transmission of reflected/emitted energy from the surface to the remote sensor through the intervening atmosphere.
- 36. 5. Recording of EMR at the sensor and transmission of the recorded information (sensor data output) to the ground. 6. Preprocessing, processing, analysis and interpretation of sensor data. 7. Integration of interpreted data with other data sources for deriving management alternatives and applications.
- 37. APPLICATION OF REMOTE SENSING Agriculture:• Crop condition assessment. • Crop yield estimation Urban Planning:• Infrastructure mapping. • Land use change detection. • Future urban expansion planning
- 38. • • • • Hydrology Forestry And Ecosystem Ocean applications Disaster management
- 39. IN CYCLONE: MITIGATION PREPAREDNESS RESCUE RECOVERY SATELLITES USED: Risk modelling; vulnerability analysis. Early warning; long-range climate modelling Identifying escape routes; crisis mapping; impact assessment; cyclone monitoring; storm surge predictions. Damage assessment; spatial planning. KALPANA-1; INSAT-3A; QuikScat radar; Meteosat Example: Cyclone Lehar by KALPANA 1 Cyclone Helen by Mangalayan
- 40. IN EARTHQUAKES: MITIGATION PREPAREDNESS RESCUE RECOVERY SATELLITES USED Building stock assessment; hazard mapping. Measuring strain accumulation. Planning routes for search and rescue; damage assessment; evacuation planning; deformation mapping. Damage assessment; identifying sites for rehabilitation. PALSAR; IKONOS 2; InSAR; SPOT; IRS The World Agency of Planetary Monitoring and Earthquake Risk Reduction (WAPMERR) uses remote sensing to improve knowledge of building stocks — for example the number and height of buildings. High resolution imagery can also help hazard mapping to guide building codes and disaster preparedness strategies.
- 41. IN FLOODS: MITIGATION PREPAREDNESS RESCUE RECOVERY SATELLITES USED Mapping flood-prone areas; delineating flood-plains; land-use mapping. Flood detection; early warning; rainfall mapping. Flood mapping; evacuation planning; damage assessment. Damage assessment; spatial planning. Tropical Rainfall Monitoring Mission; AMSR-E; KALPANA I; Sentinel Asia — a team of 51 organisations from 18 countries — delivers remote sensing data via the Internet as easy-to-interpret information for both early warning and flood damage assessment across Asia. It uses the Dartmouth Flood Observatory's (DFO's) River Watch flood detection and measurement system, based on AMSR-E data, to map flood hazards and warn disaster managers and residents in flood-prone areas when rivers are likely to burst their banks. Flood In Uttarakhand Flood In Assam
- 42. IN OTHER DISASTERS: DISASTER MITIGATION PREPAREDNESS RECOVERY RESCUE SATELLITES USED DROUGHT Risk modelling; vulnerability analysis; land and water management planning. Weather forecasting; vegetation monitoring; crop water requirement mapping; early warning. Monitoring vegetation; damage assessment. Informing drought mitigation. FEWS NET; AVHRR; MODIS; SPOT VOLCANO Risk modelling; hazard mapping; digital elevation models. Emissions monitoring; thermal alerts. Mapping lava flows; evacuation planning. Damage assessment; spatial planning. MODIS and AVHRR; Hyperion FIRE Mapping fire-prone areas; monitoring fuel load; risk modelling. Fire detection; predicting spread/direction of fire; early warning. Coordinating fire fighting efforts. Damage assessment. MODIS; SERVIR; Sentinel Asia; AFIS LANDSLIDE Risk modelling; hazard mapping; digital elevation models. Monitoring rainfall and slope stability. Mapping affected areas; Damage assessment; spatial planning; suggesting management practices. PALSAR; IKONOS 2; InSAR; SPOT; IRS
- 43. 8th October 10th October 11th October 12th October 7th October, 2013: Indian Meteorological Department received information from KALPANA I, OCEANSAT and INSAT 3A Doppler radars deployed at vulnerable places, with overlap, sensors in the sea and through the ships, about a cyclone forming in the gulf between Andaman Nicobar and Thailand named PHAILIN.
- 44. 8th October, 2013: IMD confirmed cyclone formation and predicted it as “severe cyclone” and its effects would be felt from Kalingapatnam in Andhra Pradesh to Paradeep in Odisha, and that it would probably first strikethe port of Gopalpur in Ganjam district at about 5 pm on 12 October. The wind speed could touch 200(km/h). 10th October, 2013: IMD prediction of a severe cyclone was converted to a “very severe cyclonic storm” with wind speeds up to 220 kmph. the US Navy’s Joint Typhoon Warning Centre predicted it would have wind speeds up to 315 km/h. 12th October, 2013: The “very severe” cyclonic storm had its landfall at Gopalpur port at about 9 pm with a wind speed of 200 km/h.
Editor's Notes
- #40: Meteorologists have used satellite images to monitor storms for decades. For example, the World Meteorological Organization's Tropical Cyclone Programme uses satellite observations, together with meteorological measurements and modelling, to produce cyclone warnings. These estimate the storm's position, direction and speed, maximum wind speeds, areas likely to be affected, and likely storm surges. The programme issues these to government officials, river port authorities, the general public, coast guard, non-governmental organisations and cyclone preparedness programmes across the world.
- #41: Acronyms: Satellite Pour l'Observation de la Terre (SPOT); Thematic Mapper (TM); Advanced Very High Resolution Radiometer (AVHRR); Moderate Resolution Imaging Spectroradiometer (MODIS); Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER); Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM); Synthetic Aperture Radar (SAR); Phased Array type L-band SAR (PALSAR); Tropical Rainfall Measuring Mission (TRMM); Global Precipitation Measurement (GPM); Advanced Microwave Scanning Radiometer (AMSR-E); Atmospheric Infrared Sounder (AIRS)