Exam 1 Flashcards
What is remote sensing?
=> Obtain information
=> About Earth’s resources
=> From a distance
=> Using electromagnetic energy
When was the first aerial image taken?
1858, Boston (using a balloon)
Launch of Landsat 1?
July 23, 1972
Describe Earth’s landscape.
=> Geographically variable
=> Time dynamic
What is em energy?
Energy that moves with the constant velocity of light in a harmonic wave pattern
Describe electromagnetic spectrum.
=> No sharp divisions
=> Classification of em energy according to wavelength (based on what they can do for us)
List colors (wavelengths) of electromagnetic spectrum.
ROY.G.BIV (Longer Shorter)
Additive colors?
Blue, Green, Red
Subtractive colors?
Yellow, Magenta, Cyan
What dyes are present to see black? Wavelengths?
Dyes: Y, M, C
Wavelengths: None
What is frequency, wavelength, amplitude?
Frequency = Speed Wavelength = Used to describe energy Amplitude = Height
What is atmospheric scattering?
=> Redirection of EM energy by suspended atmospheric particles
Raleigh Scatter
Elastic scattering of light or other EM radiation by particles much smaller than the wavelength of the radiation. **Increases as wavelength decreases
Most common atmospheric constituents?
Nitrogen - 78%
Oxygen - 21%
Argon - 3%
Define spectral signatures.
=> An objects unique distribution of reflected, emitted, and transmission of EM energy
What wavelengths and frequencies are considered most harmful to humans?
Short and fast
If image is 1,000 by 1,000 and fit to frame?
Meta data tells width and height (7,000 x 7,000). Looking at 1/49
Define analog remote sensing.
=> Obtain info
=> Earth
=> Distance
=> B, G, R, NIR (0.4 - 0.9 um)
List process of analog remote sensing.
- Sun
- Scattering
- Reflectance
- Airplane
- Photo
- Map
7 P’s of A.P.I.
Pattern Shadow Shape Size Site Tone Texture
Why do federal agencies prefer color-infrared?
Visible and NIR give sharper, clearer and more info
Film types?
=> Black and White (All visible light (B, G, R))
=> Black and White-infrared (G, R, NIR)
=> Color (0.4 - 0.7 um)
=> Color-infrared (G, R, NIR)
CIR and red shift?
Healthy veg. is seen as bright red, old veg. has lengthy shadows, and less healthy veg. is more magenta
List the process of digital remote sensing.
- Sun
- Scattering
- Reflectance off earth’s surface
- Satellite
- Digital image
- Map
Define digital remote sensing.
=> Obtain info
=> About Earth
=> From a distance
=> using visible, near, mid and far infrared
What is a digital image?
=> Grid of #s used to control the brightness of each pixel (DNs) in the grid.
Values of DNs?
Real: B, G, R; DEM = DI
Category: Land cover/use = Map
What does SEA stand for?
Slope, Elevation, Aspect
How many bits are there in a byte?
1 Byte = 8 bits
30x30 m or 5x5 m, which is better?
5x5 m is 36 times better
Spatial, Spectral, Radiometric, and Temporal? (Image resolution)
Spatial: Size of pixel
Spectral: Width of spectrum
Radiometric: Level of detail
Temporal: Time between images
Which display would be best suited for on screen digitizing to update road features for a GIS?
Color Infrared
Which individual band would be best for identifying structural differences within the highly vegetated area?
Red
What does Meta data provide in ERDAS?
Statistics
What band is best for identifying water?
Band 4
EM Spectrum “ “?
” “ = controls interaction of energy (visible)
How do dry areas and water appear on ERDAS?
Water = Black (absorbs energy)
Dry areas = White (reflects energy)
Visible, NIR, MIR, and FIR “ “
Visible = "pigments" (0.4 - 0.7 um) NIR = "cell structure" (0.7 - 1.3 um) MIR = "moisture" (1.3 - 3.0 um) FIR = "thermal" (7.0 - 15.0 um)
