Exam II Flashcards

1
Q

What are biophysical variables?

A

Characteristics a satellite image can sense

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2
Q

List direct biophysical variables?

A
  • x, y
  • elevation
  • color
  • biomass
  • moisture
  • heat
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3
Q

List hybrid biophysical variables?

A
  • land cover/ use
  • stress
  • productivity
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4
Q

What is a Geotiff?

A

A TIFF file that has been geocoded

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5
Q

What has better resolution, TM or MSS?

A

Thematic mapper (TM) has better resolution (16 scan lines) than Multispectral Scanner (MSS) (6)

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6
Q

Landsat vs SPOT?

A

Landsat (whiskbroom scanner):
- MSS, TM
SPOT (pushbroom scanner):
- Pan, HRV

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7
Q

Radiometric correction, why?

A
  1. Large area
  2. Difference sum angles
  3. Extend results to other areas
  4. Compare to other data
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8
Q

What are detector errors?

A

Errors that affect the quality of a satellite data set

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9
Q

Types of detector errors?

A
  1. Line dropout - one detector fails (Fix: Avg. #s) (Results in failure from Landsat**)
  2. Destripping - detector drift
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10
Q

What is histogram subtraction?

A

Adjusting for atmospheric scatter via simple math

- subtract min DN from each band

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11
Q

What happens as a result of Raleigh scatter?

A

DNs increase

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12
Q

What is histogram regression?

A

Adjusting for atmospheric scatter via regression techniques

  • No ref. in IR Regions
  • Regress pixels in clear deep water and shadows
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13
Q

What is geometric correction?

A

Projecting image data onto a flat plane to conform to a map projection

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14
Q

Ways to tell if an image has been geometric corrected?

A
  1. Inquire
  2. Measuring tool
  3. Check MetaData
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15
Q

Geometric correction, step 1?

A

Locate GCP’s

  • pixels found on map and image
  • min # of GCP’s = ((t+1)(t+2)/2
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16
Q

Geometric correction, step 2?

A

Create transformation model

  • determine RMS error
  • RMS -> on avg.
  • to decrease RMS error
17
Q

Geometric correction, step 3?

A

Perform G.C.

  • Spatial interpolation
  • Spectral interpolation
  • Bilinear interpolation (img. -> smooth)
  • Cubic convolution
18
Q

Types of geometric correction?

A

Georeferencing (assigns map coordinates to an img)

Registration (Landsat 5)

19
Q

How do satellites find space?

A

Telemetry