1. Geography 372 Introduction to Remote Sensing
University of Maryland
Compton Tucker & Megan Weiner

2. Remote Sensing Creed I want to understand the world
I must use the electromagnetic spectrum (few other options)
I will not be limited by a sensory system (the human eye) optimized for viewing things in the light from a 6000 K star 93M miles away, whose electromagnetic irradiance also has to pass through Earth’s N2-O2 planetary atmosphere

3. All alone in our neighborhood of space
Apollo 12’s Classic Earth Rise from Moon

6. Remote Sensing Systems
How do we discuss and catagorize remote sensing?
“the resolutions”
Spatial Resolution -- what size we can resolve
Spectral Resolution -- what wavelengths do we use
Radiometric Resolution -- degree of detail observed
Temporal Resolution -- how often do we observe

7. Near-infrared separates conifers (darker) from deciduous trees
True & False Color Ikonos Satellite Data Beltsville Agricultural Research Center
In visible light these trees look the same
Near-infrared separates conifers (darker) from deciduous trees nm

8. Spatial resolution
Each square in the image is one digital number for each spectral band. The dimensions of the square determines spatial resolution.

9. Better spatial resolution
Mars Orbiter 2000 resolution = ~10 m
Mars “Face” Viking 1976 resolution = ~200 m

10. Multistage Remote Sensing

11. Ground-based remote sensing

12. Air Photo: color film, airplane, 1-2 m detail Timothy Lake, OR

13. Landsat 30 m
Mt. St. Helens Mt. Adams
Columbia River

14. Yellowstone N.P.
Olympic Pen.
Columbia River
Mt. St. Helens
AVHRR 1 km

15. Satellite Remote Sensing of Earth
SeaWiFS Land-Ocean Chlorophyll September 1997 to present …

16. The Electromagnetic Spectrum
Remote sensing uses the radiant energy that is reflected and emitted from Earth at various “wavelengths” of the electromagnetic spectrum
Our eyes are only sensitive to the “visible light” portion of the EM spectrum
Why do we use nonvisible wavelengths?

17. Our Sun emits more light in the visible than any other part of the spectrum.
our star

18. Amount of solar energy hitting Earth’s outer atmosphere is ~1370 watts/m2

19. Rayleigh Scattering: why the sky is blue

20. Remote Sensing Systems: the Human Eye
Spectral Resolution: µm
Spatial Resolution: ~ m
Radiometric Resolution: ~16-32 shades B/W or ~100 colors

21. Invertebrate remote sensing
Insects have remote sensing capabilities quite different from vertebrates and the octopus

22. Key Milestones in Remote Sensing of the Environment
1826 – Joseph Niepce takes first photograph
1858 – Gaspard Tournachon takes first aerial photograph from a balloon
1913 – First aerial photograph collected from an airplane
1935 – Radar invented
1942 – Kodak patents color infrared film
1950s – First airborne thermal scanner
1957 – First high resolution synthetic aperture radar
1962 – Corona satellite series (camera systems) initiated by the Intelligence community
1962 – First airborne multispectral scanner
1972 – ERTS-1 Launched – First Landsat satellite
A good way to understand the science/technology of remote sensing is to briefly review its history
In reality, the science of remote sensing dates from the 1960s with the development of electro-optical remote sensing systems
The entire science of remote sensing was revolutionized in the early 1970s with the launch of the Earth Resources Technology Satellite-1, which was later renamed into Landsat
ERTS-1 provided the first synoptic view of the entire earth for civilian satellites

23. Early photograph by J. Niepce circa1830
Remote sensing has its foundation in photography.
Joseph Niepce created the first photograph in France in 1826
This photograph took 8 hours to expose
The original concepts of Diecpe were improved upon by Louis Daguerre, who created the first photographic plate, e.g., a film that could be exposed and processed.
Then, William Talbot invented the process whereby film negatives could be used to create positive prints.

24. Nadir in his balloon
The next development in remote sensing occurred in 1858
This is when Gaspard Tournachon (who liked to call himself Nadar) took a picture from a balloon, creating the first aerial photograph

25. Nadir photograph of Paris
Here is an aerial photograph that Tournachon took along the riverfront in St. Louis
Demonstrated that photography could be used to create an accurate spatial representation of the earth’s surface
Up until this time, map makers were limited in their ability to make renditions of the earth’s surface based upon tedious and time consuming ground-based surveys

26. Balloon Photo of Boston 1836

27. Thaddeus Lowe’s Civil War Balloons U.S.Army of the Potomac 1861-1865
Massachusetts’ man, Professor and visionary, Lowe Observatory/Calif.
Platform: Balloon
Sensor: Telescope
Data System: Telegraph

28. Thaddeus Lowe, circa 1861-1865 remote sensing for military purposes
Thaddeus Lowe, circa remote sensing for military purposes. Then, as now, newest developments are always in the military sphere

29. Remote sensing early in the airplane era
When airplanes were invented in the early 1900s, this lead to the use of this platform for collection of aerial photographs
Aerial photography was extensively used in WWI
Top is a hand held operation
Bottom is a mounted camera system

30. U-2 Spy Plane 1954-1960 Flew at 70,000’ over USSR air defenses

31. SR-71 Blackbird super-sonic spy plane
This was followed by the SR 71

32. CIA’s Corona Program 1960-1972 >100 missions
Followed after U-2s…
Platform: Spacecraft
Sensor: Camera
Data System: Film Drop
Started: August 1960
Coverage: Bil mi2
Spatial Resolution: early 13 m, later 2 m
Spectral Resolution: visible and visible-near infrared (both film)
Radiometric Resolution: equivalent 24 to 26 (4 to 6 bits)

33. CIA’s Corona Program Washington Monument 1967

34. Ikonos 1 m panchromatic imagery
2000
We are now to the point where we can collect high resolution photography from spaceborne digital camera systems on a commercial

35. MODIS Land Reflectance and Sea Surface Temperature