sample copy. not for distribution.camera is vertical and the plane of the photograph (film) is...

Sample Copy. Not For Distribution.

i

Photogrammetry, GIS

&

Remote Sensing Quick Reference Book


ii

EDUCREATION PUBLISHING

Shubham Vihar, Mangla, Bilaspur, Chhattisgarh - 495001

Website: www.educreation.in ________________________________________________________________

© Copyright, 2017, S.S. Manugula, V. Bommakanti

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form by any means, electronic, mechanical, magnetic, optical, chemical, manual, photocopying, recording or otherwise, without the prior written consent of its writer.

ISBN: 978-1-5457-1310-5

Price: ` 155.00

The opinions/ contents expressed in this book are solely of the authors and do not represent the opinions/ standings/ thoughts of Educreation or the Editors . The book is released by using the services of self-publishing house.

Printed in India


iii

Photogrammetry,

GIS & Remote

Sensing Quick Reference Book

Dr. S.S. Manugula

Dr. Veeranna Bommakanti

EDUCREATION PUBLISHING (Since 2011)

www.educreation.in


iv

Preface ______________________________________________________

This book has been written for use in classrooms by both

the instructor and the students and also for independent

study in the coming decades.

The main intention for writing this book is to make

the subject very easy at the same time to cover the

syllabus for undergraduate students. The basic concepts

of Photogrammetry, Remote Sensing & GIS all are

included in a single book which helps the students to the

face the exams easily and very quickly.

This book is intended to be basically utilized as a quick reference in support to various text books. This

book also covers few real images which I used in the

industries during my visit to UAE (Dubai & Abu Dhabi) for

set up a project for Military Survey Department.

Dr. S.S. Manugula

Dr. Veeranna Bommakanti


v

Content List

Sr. Content Page

1.

Introduction to Photogrammetry

Types of Photogrammetry Principle

and types of aerial photographs,

Geometry of vertical aerial photograph, Scale and Height

measurement on single vertical

aerial photograph, Height

measurement based on relief

displacement, Fundamental of

stereoscopy, fiducial points, parallax measurement using fiducial line.

1-15

2. Remote Sensing

Basic concepts of Remote Sensing,

Data and Information, Remote

sensing data collection, Remote

sensing advantages & Limitations, Remote sensing process.

Electro-magnetic Spectrum, Energy

interactions with atmosphere and

earth surface features (soil, water,

vegetation), Indian satellite and

sensors Characteristics, Resolution, Map and Image and False color

composite, introduction to digital

data analysis. Elements of visual

interpretation techniques.

16-46

3. Geographic Information System Introduction to GIS, Components of

GIS, Geospatial Data- Spatial Data,

and Attribute data-Joining Spatial

and Attribute data: GIS Operation:

47-68


vi

Spatial Data Input-Attribute data

Management.-Data display- Data

Exploration-Data Analysis.

COORDINATE SYSTEMS: Geographic

Coordinate System: Approximation of Earth, Datum; Map Projections:

Types of Map Projection Map

projection parameters-Commonly

used Map projections-Projected

coordinate System.

4. Vector Data Model Representation of simple features-

Topology and its importance;

coverage and its importance:

coverage and its data structure,

Shape file; Data models for

composite features Object Based Vector Data Model; Classes and

their Relationship; The geo database

data model; Geometric

representation of Spatial Features

and data structure, Topology rules

69-82

5. Raster Data Model

Elements of the Raster data model,

Types of Raster Data, Raster Data

Structure, Data Conversion,

Integration of Raster and Vector

Data.

Data Input: Metadata, Conversion of Existing data, creating new data;

Remote Sensing data, Field data,

Text data, Digitizing, Scanning, on

screen digitizing, importance of

source map, Data Editing.

83-107

6. UNIVERSITY QUESTION BANK

(UQB)

108-131


Photogrammetry, GIS & Remote Sensing

1

Chapter 1

Introduction to Photogrammetry ______________________________________________________

Introduction

Photogrammetry is a Branch of Remote Sensing.

Defined as the art, science, and technology of obtaining

reliable information about physical objects and the

environment. This is done through a process of recording,

measuring, and interpreting aerial and terrestrial

photographs.

In a sense, the word photogrammetry may be analyzed in two parts:

photo- meaning ―picture," and

grammetry - meaning "measurement."

Therefore; photo-measurement.

Types of Photogrammetry

Photogrammetry was invented in 1851 by laussedat, and

has continued to develop over the last 140 years. Over

time the development of photogrammetry has passed through the phases of

1. Plane table photogrammetry

2. Analog photogrammetry

3. Analytical photogrammetry

4. Digital photogrammetry (latest)


Dr. S.S. Manugula, Dr. Veeranna Bommakanti

2

The traditional, and large, application of photogrammetry

is to extract topographic information (e.g., topographic

maps) from aerial images. However, photogrammetric

techniques have also be applied to process satellite

images and close range images in order to acquire

topographic or non-topographic information of

photographed objects.

1. Plane table photogrammetry: Prior to invention of

airplane, photographs taken on the ground where used

to extract the relationships between objects using

geometric principles. This was during the phase of

table photogrammetry

2. Analog photogrammetry: In analog photogrammetry, starting with stereo measurement in

1901, optical or mechanical instruments were used to

reconstruct three-dimensional geometry from two

overlapping photographs. The main product during this

phase was topographic maps.

3. Analytical photogrammetry: In Analytical

photogrammetry, the computer replaces some expensive optical & mechanical components. The

resulting devices were analog/digital hybrids.

Analytical aero triangulation, analytical plotters,

orthophoto projectors were the main developments

during this phase. Outputs of analytical

photogrammetry can be topographic maps, but also can be digital products, such as digital maps and

DEMs.

4. Digital photogrammetry (latest): Digital

photogrammetry is photogrammetry as applied to

digital images that are stored and processed by the

computer. The images can be obtained by scanning the photographs or by directly from digital cameras.

Many photogrammetry tasks can be highly automated

in digital photogrammetry (e.g., automated DEM

extraction and digital orthophoto generation). Digital

photogrammetry can also be called softcopy

photogrammetry.



3

The output of the product is in the digital form, such as

digital maps, DEMs, and digital Orthophotos saved on the

computer media. With the development of digital

photogrammetry the photogrammetric techniques are

more closely integrated into Remote Sensing and GIS.

Principle

The principle involved in the aerial photography is ―The taking of photographs of a location @ regular intervals

from an aero plane/satellite along a define line at the

certain height above the mean sea level at a specified

speed of movement.”

Further Explanation: -- Photographs are taken from

aero planes and satellites with metric and Non-metric cameras. These photographs are collected with forward

overlap between each photograph as they are captured

down a flight line. Mapping areas may require multiple

flight lines in order to include all necessary mapping area

within the imagery. In these cases, the imagery flight

lines are flown so that they overlap (side lap). Near



4

vertical aerial photography is flown with a forward lap of

60 percent and side lap of 30 percent.

Based on the various input parameters and after

generating Aero Triangulation (AT) the compiler able to

see stereo and map the required features.

Planimetric and topographic features are collected from

natural colour near vertical aerial photography.

Planimetric and topographic mapping is generally the

base mapping data set in a GIS or engineering data set.

The accuracy of computations and queries made from

these base mapping data sets is based on their

thoroughness and accuracy.

Colour aerial photography provides the clarity and spatial resolution required to achieve most large- and small-scale

mapping accuracies.

Types of Aerial Photographs

The axis of camera may not be remaining exactly

vertical. So the aerial photographs are classified into 4

major types.

They are

1) Aerial/Vertical photographs

2) Near vertical photographs

3) Tilted photographs

4) Horizontal/terrestrial photographs

1) Vertical Photographs: The photographs taken

from an aero plane with camera axis coincide with the direction of gravity are called Vertical

Photographs. These photographs are commonly

used for topographic mapping and planimetric

mapping.

2) Near vertical photographs: The photographs

taken from an aero plane with camera axis makes

an angle between 1degree and 3 degree from the direction of gravity. For all practical purposes,



5

these photographs are considered as vertical

photographs.

3) Tilted / oblique photographs: oblique

photographs and images are similar to aerial

photographs and images, except the camera axis is

intentionally inclined at an angle with the vertical.

This can be further divided into Low oblique (camera 30º) and High oblique (camera 60º) from

the vertical. These are commonly used for

reconnaissance and corridor mapping applications.

4) Horizontal or Terrestrial photographs:

Terrestrial or ground-based photographs and images

are taken with the camera stationed on or closed to the Earth‘s surface. These are commonly used for

applications involved with archeology, geomorphology,

civil engineering, architecture, industry, etc.

Geometry of Vertical Aerial Photograph

Geometry of the single aerial photograph

The geometry of a single vertical aerial photograph is

illustrated in Figure 1. In a vertical aerial photograph the optical axis of the

camera is vertical and

the plane of the

photograph (film) is

horizontal. The point

where the optical axis intersects the

photograph is termed

the centre point or

principal point of the

photograph. This can

be located on an aerial

photograph as the intersection of lines drawn between opposite fiducial

marks in the margins of the print. In a perfectly vertical



6

aerial photograph the principal point also represents the

plumb point or nadir point which is the photographic

position representing the point on the earth's surface

vertically beneath the camera lens at the time of

exposure. In practice a vertical aerial photograph is rarely

absolutely vertical and the nadir point and the centre

point do not coincide exactly, the usually small difference being the result of tilt. The distance between the camera

lens and the ground represents the flight height of the

aircraft and the focal length is the distance between the

camera lens and the film.

The scale & Height measurement on a single

vertical aerial photograph

Scale: the ratio of the distance between two points on

a photo to the actual distance between the same two

points on the ground (i.e. 1 unit on the photo equals

"x" units on the ground). If a 1 km stretch of highway

covers 4 cm on an air photo, the scale is calculated as

follows:

Large Scale - Larger-scale photos (e.g. 1:25 000)

cover small areas in greater detail. A large scale

photo simply means that ground features are at a

larger, more detailed size. The area of ground coverage that is seen on the photo is less than at

smaller scales.

Small Scale - Smaller-scale photos (e.g. 1:50 000)

cover large areas in less detail. A small scale photo

simply means that ground features are at a smaller, less detailed size. The area of ground



7

coverage that is seen on the photo is greater than

at larger scales.

Another method used to determine the scale of a photo is

to find the ratio between the

camera's focal length and the

plane's altitude above the ground being photographed

f = focal length 6‖ or 152.4

mm is common

H‘ = height of plane above ground

h = height (elevation) of

ground

H = height of place above

datum [altimeter reading

(2% error)]

One of the most significant geometric relationships is

that the angles are subtended at a camera lense by an

object and by its photographic image. In other words the

triangles abc and cde are similar and it follows that the

ratio of object size (O) to image size(i) is the same as the ratio of focal length (f) to flight height (H) , or

The ratio of image to object size is the general scale of the aerial photograph and it follows that the scale may be

determined if the camera focal length and the flight

height are known:

It is also very important to remember that the flight height refers to a distance above the ground directly



8

below and not necessarily to the attitude (height above

sea level or the base airport) of the aircraft. For this

reason a more precise restatement of equation 2 should

modify as

Heights Measurement

In a vertical aerial

photograph the

displacement of

images is in a radial

direction from the center point of the

photograph.

This displacement is

termed the radial

displacement due to

relief and represents an error

in map positioning

For any one aerial photograph the amount of radial

displacement, m of the top of an object from its base

can be determined by the relation

In which r= radial distance on the photograph from

the center point to the top of the image displaced, h=

height of the object displaced, and H = flight height.

Rearranging the equation (4) yields a convenient

expression for estimation the height of an object on a

photograph by measuring its redial displacement.



9

Fundamental of stereoscopy

What is a Stereoscopy?

Stereoscopy is the science and art that deals with the use of

binocular vision for the

observation of overlapping

photographs or other perspective

views and the method by which

such views are produced.

- Essentially most of us with ―normal‖ eyesight have

stereoscopic vision (i.e. the

ability to see and appreciate

depth of field through the

perception of parallax.)

The stereoscopic methods

present two different offset

images separately to the left

and right eye of the viewer. These two images when combined the brain have the

capability to give the perception of 3D depth.

Based on the stereo vision i.e. 3D perception one can

get and extract more information from the stereo

images.

Proper Use of Stereoscopes

The following are some guidelines that will help you

use your stereoscopes properly. They are important

and should be kept in mind when performing stereo

based interpretations:

1. Be sure that the photos are properly aligned,

preferably with the shadows toward the viewer.


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