1. Remote sensing and geography
GEOG3610 Remote Sensing and Image Interpretation
Remote sensing and geography
Remote Sensing and Geography

2. Remote sensing and geography
GEOG3610 Remote Sensing and Image Interpretation
Remote sensing and geography
What is remote sensing?
Development of remote sensing
Observations of the Earth’s surface
Communication and data collection systems
Image Processing
Use of remote sensing in geography
Remote Sensing and Geography

3. GEOG3610 Remote Sensing and Image Interpretation
What is remote sensing?
Remote sensing is the acquisition of information about an object without physical contact.
It includes photographic and digital remote sensors.
Aircraft and satellites are major platforms for the sensors.
Remote Sensing and Geography

4. GEOG3610 Remote Sensing and Image Interpretation
What is remote sensing?
Observation of a target by a device separated from it by some distance
What is measured?
“lights” or “colour” - to discuss later
How are the photographs and images created
airborne and satellite data
How can I use the images
identifying things, interpretation, see the change
Remote Sensing and Geography

5. Remote sensing systems
GEOG3610 Remote Sensing and Image Interpretation
Remote sensing systems
Information products
Reference data
Visual
Digital
Pictorial
Digital
Interpretation and analysis
Data products
Sensing systems
Users
Remote Sensing and Geography

6. Development of remote sensing
GEOG3610 Remote Sensing and Image Interpretation
Development of remote sensing
The term “remote sensing” was coined in the early 1960’s by geographers in the Office of Naval Research of USA to apply to the information derived from photographic and non-photographic instruments.
Remote Sensing and Geography

7. Remote sensing prior to 1960
GEOG3610 Remote Sensing and Image Interpretation
Remote sensing prior to 1960
Aristotle (2300 years ago): “camera obscura”.
photographic process (Daguerre and Niepce) - “daguerrotype”.
first known balloon photograph (Tournachon - “Nadar”, France).
Air photograph - developed for military purposes.
Between WW1 and WW2, civilian use of air photographs.
Remote Sensing and Geography

8. 1860 picture of Boston Harbour
GEOG3610 Remote Sensing and Image Interpretation
1860 picture of Boston Harbour
This 1860 picture of Boston Harbour is thought to be the first aerial photograph taken in the US. The exposure was made from a balloon at an altitude of about 365m above the ground
Remote Sensing and Geography

9. Old air-borne platforms
GEOG3610 Remote Sensing and Image Interpretation
Old air-borne platforms
Above: Stalwart pigeon photographers prepare to work. The tiny pigeon cameras were designed in 1903 and weighed about 70g. Right: Peering down a camera viewfinder from the open cockpit of a Curtiss Jenny, a flier practices the early techniques of aerial photography.
(Courtesy Strain and Engle, 1992)
Remote Sensing and Geography

10. GEOG3610 Remote Sensing and Image Interpretation
Airphoto – Hong Kong 1945
Remote Sensing and Geography

11. GEOG3610 Remote Sensing and Image Interpretation
Remote sensing since 1960
TIROS-I: the first meteorological satellite: low resolution sensor
ERTS-1 (changed to Landsat in 1975): MSS and HBV
NOAA: AVHRR
Landsat-4: TM
SPOT-1: PAN and XS
since late 1980s: more earth observation satellites, e.g. Russian, Indian, Japanese, Chinese and others
1999: IKONOS commercial ‘small’ satellites
Remote Sensing and Geography

12. GEOG3610 Remote Sensing and Image Interpretation
1960: TIROS-1
NASA/DOD
Remote Sensing and Geography

13. GEOG3610 Remote Sensing and Image Interpretation
1972: ERTS 1
Solar array
Return beam vidicon (RBV) cameras
Multispectral scanner (MSS)
Data collection antenna
Remote Sensing and Geography

14. GEOG3610 Remote Sensing and Image Interpretation
1981: NOAA
TIROS-N
Remote Sensing and Geography

15. GEOG3610 Remote Sensing and Image Interpretation
1982: Landsat 4
Remote Sensing and Geography

16. GEOG3610 Remote Sensing and Image Interpretation
1983: NOAA 8
Advanced TIROS-N (ATN)
Remote Sensing and Geography

17. GEOG3610 Remote Sensing and Image Interpretation
1986: SPOT 1
SPOT - Système Pour l’Observation de la Terre - initiated by French government in late 1970’s.
SPOT 1: 21/2/1986 SPOT 2: 21/1/1990 SPOT 3: 23/9/1993 SPOT 4: 26/3/1998 SPOT 5: 4/5/2002
All currently operational except SPOT 3, which is recently lost (1997).
Remote Sensing and Geography

18. GEOG3610 Remote Sensing and Image Interpretation
1995: Radarsat
Launched 1995 (Canada Space Agency) sun-synchronous, km orbit, repeat 24 days Sensor: C-band SAR
Remote Sensing and Geography

19. 1999: EOS-AM 1 (Terra Spacecraft)
GEOG3610 Remote Sensing and Image Interpretation
1999: EOS-AM 1 (Terra Spacecraft)
Terra is the first of the NASA’s Earth Observing System satellite series. It was launched in December 1999 and activated for science operation on 24 February 2000.
Courtesy terra.nasa.gov
Remote Sensing and Geography

20. GEOG3610 Remote Sensing and Image Interpretation
1999: IKONOS
The first ‘small’ satellite launched and operated by a commercial company (SpaceImaging)
Weight 1600 pounds
Launched on 24 September 1999
Ground resolution:
Panchromatic: 1m
Multispectral: 4m
Remote Sensing and Geography

21. GEOG3610 Remote Sensing and Image Interpretation
2001: QuickBird
Commercial remote sensing system developed and operated by DigitalGlobe
Launched on 18 October 2001
Ground resolution:
Panchromatic: 61cm
Multispectral: 2.44m
Remote Sensing and Geography

22. Comparison of the two major periods in the history of remote sensing
GEOG3610 Remote Sensing and Image Interpretation
Comparison of the two major periods in the history of remote sensing
Remote Sensing and Geography

23. How does remote sensing work?
GEOG3610 Remote Sensing and Image Interpretation
How does remote sensing work?
recording and measuring electromagnetic radiation from the target.
This recording and measurement can be taken by airborne or satellite sensors.
Remotely sensed images are rectified and enhanced to show information better.
We interpret the images to get information on given locations for mapping, management, etc.
Remote Sensing and Geography

24. Observation of the earth’s surface
GEOG3610 Remote Sensing and Image Interpretation
Observation of the earth’s surface
For geographers, we use remote sensing to observe the Earth’s surface.
Air photographs offer detailed view of the Earth’s surface but limited by many factors.
Satellite photographs and images provide less detailed but more variety of information with a large and regular coverage.
Remote Sensing and Geography

25. Causes of differences in scale of aircraft and satellite observations
GEOG3610 Remote Sensing and Image Interpretation
Causes of differences in scale of aircraft and satellite observations
Satellite
Aircraft
Hundreds of kilometres
Thousands of metres
Remote Sensing and Geography

26. Passive and active remote sensing
GEOG3610 Remote Sensing and Image Interpretation
Passive and active remote sensing
Passive remote sensing: the sensor detects the reflectance of sunlight from the surface
e.g. photographs, multispectral scanners
Active remote sensing: the sensor detects the reflectance of the signal sent by the remote sensing system
e.g. RADAR
Remote Sensing and Geography

27. Passive remote sensing
GEOG3610 Remote Sensing and Image Interpretation
Passive remote sensing
Remote Sensing and Geography

28. GEOG3610 Remote Sensing and Image Interpretation
Active remote sensing
Remote Sensing and Geography

29. Communication and data collection systems
GEOG3610 Remote Sensing and Image Interpretation
Communication and data collection systems
Remotely sensed data has to be transmitted back to the Earth.
A network of satellite receiving stations have been established over the world to receive data.
Some satellite data can be directly received by small instruments.
Data are available through variable commercial channels (e.g. EOSAT).
Remote Sensing and Geography

30. Overview of data collection and platform location system
GEOG3610 Remote Sensing and Image Interpretation
Overview of data collection and platform location system
Remote Sensing and Geography

31. GEOG3610 Remote Sensing and Image Interpretation
Image processing
Digital images are the major types of today’s remotely sensed data.
They are fundamentally numbers.
To make sense of them, a technology called image processing is employed to distort, enhance and extract information from the images.
Image processing and interpretation are the focus for this subject.
Remote Sensing and Geography

32. Use of remote sensing in geography
GEOG3610 Remote Sensing and Image Interpretation
Use of remote sensing in geography
Remote sensing can bring us accurate, cheap and frequently updated information about the Earth’s surface.
GIS is the optimum tool to handle and integrate large amount of spatially referenced data including remotely sensed data.
Many things and phenomena in the real world are spatially referenced.
Remote Sensing and Geography

33. Some examples of applications
GEOG3610 Remote Sensing and Image Interpretation
Some examples of applications
Agriculture
Forestry
Environment
Urban and regional planning
Mineral resources
and many more...
Remote Sensing and Geography