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.
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)
Modern surveying techniques
1. Basics of surveying
2. Modern surveying equipments
3. Remote sensing
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
• Different method and instrument are being used to
facilitate the work of surveying.
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
• 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.
• Recently electronic digital levels have evolved as a
result of development in electronics and digital image
• 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.
SALIENT FEATURES OF
• Fatigue-free observation as visual staff reading by the
observer is not required.
• User friendly menus with easy to read, digital display
• Measurement of consistent precision and reliability
due to automation.
• Automatic data storage eliminates booking and its
• Fast, economic surveys resulting in saving in time (up
to 50% less effort has been claimed by
• Data on the storage medium of the level can be
downloaded to a computer enabling quick data
reduction for various purposes.
COMPONENTS OF DIGITAL
• 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
• Both digital level and associated staff are
manufactured so that they can be used for both
conventional and digital operations.
• 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.
• 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.
• Various capabilities of digital levels are as follows:
1. measuring elevation.
2. measuring height difference.
3. measuring height difference with multiple
6. setting out with horizontal distance
7. levelling of ceilings
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
• The following photographs show different types of
OPERATION WITH EDMI
• Measurement with EDMI involves four basic steps:
(a) Set up
• Setting up: The instrument is centered over a station
by means of tribrach. Reflector prisms are set over
the remote station on tribrach.
• 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
• Recording: The information on LCD panel can be
recorded manually or automatically. All meteorological
parameters are also recorded.
ERROR IN MEASUREMENT
1. Instrument errors :
• centering at the master and slave station.
• pointing/sighting of reflector.
• entry of correct values of prevailing atmospheric
2. Atmospheric errors :
(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
• These instruments can record horizontal and vertical
angles together with slope distance and can be
considered as combined EDM plus electronic
• 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.
• 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
all capabilities of theodolites
electronic recording of horizontal and vertical
storage capabilities of all relevant measurements
(spatial and non-spatial attribute data) for
manipulation with computer.
SALIENT FEATURES OF TS
• TS is a fully integrated equipment that captures all the
spatial data necessary for a three-dimensional
• 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
• 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
• Some instruments and/or data loggers can be
interfaced directly with a computer for immediate
processing and plotting of the data (Kavanagh, 2003).
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
Missing line measurement (MLM)
Remote distance and elevation measurement
Layout or setting out operation
For details on above functions, one can refer to the
user manual of any TS.
Different Types of TS and
• 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
REMOTE SENSING SYESTEM
• A typical remote sensing system consists of the
(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
• The following steps indicate how remotely sensed
data gets converted into useful information:
1. Source of EM energy (sun/self emission: transmitter
2. Transmission of energy from the source to the surface
of the earth and its interaction with the atmosphere
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
5. Recording of EMR at the sensor and transmission of
the recorded information (sensor data output) to the
6. Preprocessing, processing, analysis and
interpretation of sensor data.
7. Integration of interpreted data with other data
sources for deriving management alternatives and
APPLICATION OF REMOTE
Agriculture:• Crop condition assessment.
• Crop yield estimation
Urban Planning:• Infrastructure mapping.
• Land use change detection.
• Future urban expansion planning
Identifying escape routes;
storm surge predictions.
Cyclone Lehar by KALPANA 1
Cyclone Helen by Mangalayan
Building stock assessment;
Planning routes for search
identifying sites for
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.
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
land and water
crop water requirement
FEWS NET; AVHRR;
digital elevation models.
Mapping lava flows;
MODIS and AVHRR;
monitoring fuel load;
predicting spread/direction of
Sentinel Asia; AFIS
Monitoring rainfall and slope
InSAR; SPOT; IRS
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.
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
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