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SubjectDatabase Management Information System &

Applications of Remote sensing and GIS

“Introduction to Image Interpretation”Topic:

Dated: 21/10/14

Presented by

Rehana Jamal

Lecture # 02 Part-II

Section-II “Applications of Remote sensing and GIS”

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1. INFORMATION EXTRACTION IN REMOTE SENSING

2. IMAGE INTERPRETATION

3. INTERPRETATION ELEMENTS/KEYS

Database Management Information System & Applications of Remote sensing and GIS

Subject

Dated:21/10/14Lecture#2 Part-II

Topics

Section-II “Applications of Remote sensing and GIS”

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1. INFORMATION EXTRACTION IN REMOTE SENSING

“Remote sensing is the technology allowing to obtain information of an object, area or phenomenon by means of data coming from an apparatus, which is not in physical contact with this object, area or phenomenon.”

In practice, this means that the information of the Earth's surface is obtained by sensors mounted on an airplane or a satellite.

Remote sensors record electromagnetic radiation emitted or reflected from the Earth’s surface. Different types of vegetation, soils and other features emit and reflect energy differently.

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*Energy Source or Illumination (A) *Radiation and the Atmosphere (B)*Interaction with the Target (C) *Recording of Energy by the Sensor (D)*Transmission, Reception, and Processing (E) *Interpretation and Analysis (F) *Application (G)

Process of information extraction

from remote sensing

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DIFFERENT TECHNIQUES OF INFORMATION EXTRACTION

Remote sensing:is a technique of collecting information from a distance

Remotely sensed data:

The data collected from a distance

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“Remote Sensing (RS) is the science and art of acquiring information (spectral, spatial, temporal) about material objects, area, or phenomenon, without coming into physical contact with the objects, or area, or phenomenon under investigation”

Definitions of Remote Sensing

“Remote sensing is the 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”

OR

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Two main categories of Spatial data acquisition

Ground based methods

Remote sensing methods

Real world

Real world

Observation & measurements

Spatial database

Spatial database

Observation & measurementsSensors

Image data

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“Image Interpretation”

Photographic Interpretation can be defined as: “the act of examining photographic images for the purpose of identifying objects and judging their significance” (Colwell, 1997).

Topic:2

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Image Interpretation (visual analysis)

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NEW CAMPUS(PU), LAHORE

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Can you interpret Old CIMR in PU, Lahore?

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Can you interpret New CIMR in PU, Lahore?

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What is Dead Ground Effect?

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Image Interpretation of Dead Ground Effect

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Image Interpretation (visual analysis)

Photographic Interpretation can be defined as: “the act of examining photographic images for the purpose of identifying objects and judging their significance” (Colwell, 1997).

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Two methods of information extraction from remote sensing imagery

Information extraction based on visual analysis or interpretation of data e.g. land use, soil map, updating of topographic maps from aerial

photographs

Information extraction based on semi-automatic processing by computer e.g. automatic generation of DTM, image classification and calculation of surface parameters

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Image understanding and Interpretation

1st Method

Human Vision

Interpretation elements

Stereoscopic vision

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Direct and spontaneous recognition----refers to the ability of an interpreter to identify objects or phenomena at a first glance.

By a reasoning process (logical inference) ---In the reasoning interpreter will use his professional knowledge & experience. If reasoning cannot help then field observation is required

Two situations of human vision:

i. Direct and spontaneous recognitionii By a reasoning process(logical inference)

1- Human Vision

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Direct and Spontaneous recognition

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By a reasoning process

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“A set of terms required to express and define characteristics present in pictures (that are visualized in image data) are called Interpretation elements.” e.g.

i. Tone/Hueii. Textureiii. Shapeiv. Sizev. Patternvi. Sitevii. Association

2- Interpretation elements

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1. Tone/Hue--- relative brightness of black and white image

2. Texture--- refers to the colour on the image as defined in the Intensity, Hue ,Saturation (HIS)system

3. Shape--- form characteristics many terrain objects visible in the image

4. Size--- relative or absolute

5. Pattern--- refers to the spatial arrangement objects e.g. concentric, radial---irrigation and housing have different pattern

6. Site--- relates to the topographic or geographic location

7. Association--- refers to the fact that a combination of objects makes it possible to infer about its meaning or functioning

2- Interpretation elements/Keys

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The impression of depth in real world can be realized by the pair of images of the same object taken from different positions. Such a pair of images, photographs or digital images that are separated and observed at the same time by the two eyes give images on the retinas in which objects at different positions in space are projected on relative different positions. This is called Stereoscopic Vision

Stereo grams---Pairs of images that can be viewed stereoscopically are called Stereo grams.

Convergence---Focusing both eyes to the object(point) of interest is called convergence.

3- Stereoscopic Vision

24Pocket stereoscope with original test image. Used by military to examine stereoscopic pairs of vertical aerial photographs.

Pocket and Mirror stereoscope

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Pocket and Mirror stereoscopes

Uses in Mapping applications

Vegetation

Forest

Soil

Geomorphology

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Photogrammetric plotters

Uses

Topographic Mapping

Large scale Mapping

27 Anachrome optical diopter glasses

Anachrome "compatible" color anaglyph method

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Anaglyphs

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Stereoscopic Vision and 3D Technology

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Process of visual image interpretation

Selection of image data and its hard copy prints

Use of transparencies to overlay on hard copy print of image for interpretation

Digitization of Point, Line & Polygon features in the form of line patterns on transparencies having

class codes & land cover codes.

Validation: independent assessment of accuracy

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Task on Analogue image Interpretation

Bring the following stationary in the next class:

Permanent markers of red, green, blue and black

Six A4 size transparencies

Print of the given image having size of 2 by 2 feet

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References:

www.google.com

“Principles of Remote sensing”

by Lucas L.E. Janssen

Recommended websites for notes http://userpages.umbc.edu/~tbenja1/umbc7/santabar/vol1/lec2/2-3.htmlhttp://en.wikipedia.org/wiki/Aerial_photographic_and_satellite_image_interpretationhttp://www.nrcan.gc.ca/earth-sciences/geography-boundary/remote-sensing/fundamentals/1223