Remote sensing slides

Introduction to Remote Sensing Sajid Rashid Ahmad MSc.(Pakistan), MSc.(Canada), PhD (Canada) Assistant Professor , University of the Punjab Lahore

Remote Sensing - An Overview 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.

How Remote Sensing Works Source

Sensor

Through the medium

Through the medium

Strike the target (Earth)

Data Sources

1. Satellite Images 2. Aerial Photographs

What is A Satellite Image?

Electromagnetic Spectrum 8

10

2.4

Radio

2.2

SW IR

2.0

10

5

Microwave

1.8

1.6

10

1.4 1.2

Thermal IR Reflected IR

1

Visible

-1

Ultra Violet

1.0

Near IR

10

0.8 Red 0.6 Green Blue 0.4

-4

X Rays

10

Wave length in micrometer

-6

10

Gamma Rays

Platforms • • • • •

SPOT Landsat (TM) RadarSAT NOAA ERS

SPOT

RADARSAT

LANDSAT ERS

NOAA

Multi-Spectral Images • Some Satellites Image in multiple bands at the same time: – SPOT 20m resolution

• 0.50-0.59µm - Visible Green • 0.61-0.68µm - Visible Red • 0.79-0.89µm - Infrared – LANDSAT (TM) 30m resolution • 0.45-0.52µm Visible Blue • 0.52-0.60µm Visible Green • 0.63-0.69µm Visible Red • 0.76-0.90µm Near Infrared • 1.55-1.75µm Mid Infrared • 10.5-12.5µm Thermal Infrared • 2.08-2.35µm Mid Infrared

Landsat 7 (ETM+ sensor)

Wavelength ( micrometers)

Resolutio n (m)

Band 1

0.45 - 0.515

30

Visible blue

Band 2

0.525 - 0.605

30

Visible green

Band 3

0.63 - 0.69

30

Visible red

Band 4

0.75 - 0.90

30

Near Infrared

Band 5

1.55 - 1.75

30

Mid Infrared

Band 6

10.40 - 12.5

60

Thermal Infrared

Band 7

2.09 - 2.35

30

Pan Band

.52 - .90

15

Analysis • Different RGB band combinations allow for different levels of analysis: – True Colour images (land cover detection):

True Colour

– False Colour images (vegetation

False Colour

Resolution in Remote Sensing • Resolution is : a general term use to represent : – Number of PIXEL (picture element) – Area on the earth that represented by pixel

• There are 2 type of resolutions: – Spectral Resolution – Spatial Resolution

Remote Sensing Application based on image classification and Change detection

Sept 1992

Oct 2000 Change Detection

Landsat-7 image band combination 743

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GIS/RS Softwares ESRI Products: ArcGIS ArcView 3.x ArcInfo ArcIMS etc.

MapInfo: MapInfo MapX Map Basic Etc. AutoDesk: AutoCAD Map AutoDesk World AutoDesk Design Center Etc.

Intergraph: Geomedia MicroStation Etc. Others: ILWIS Geomatica IDRISI ER Mapper ERDAS etc.