Midterm Flashcards

1
Q

better term for in situ data than “ground truth”

A

in situ ground reference data (since it also contains error)

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2
Q

remote sensing is both a ___ and a ___

A

art, science

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3
Q

the EMR reflected, emitted, or back-scattered from an object or geographic area is used as a ____ for the actual property under investigation

A

surrogate

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4
Q

3 active remote sensing techniques

A

LIDAR, RADAR, SONAR

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5
Q

most expensive part of a remote sensing system

A

people

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6
Q

way radiometric resolution is measured

A
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7
Q

EMR may be used as a ___ for the actual property under investigation

A

surrogate

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8
Q

remote sensing is both a ___ and an ____

A

science, art

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9
Q

Radiometric resolution

A

color depth or number of values that can be used for a single pixel (1 bit = 2^1 = 2 possible color values….8 bit = 2^8 = 256 possible color values)

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10
Q

rows

A

sideways (i), y-axis

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11
Q

columns

A

up and down (j), x-axis

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12
Q

aproximate wavelengths of landsat 8 bands (just B,G,R, NIR) in micrometers

A

B = 0.45 - 0.51

G = 0.53 - 0.59

R = 0.64 - 0.67

NIR = 0.85 - 0.88

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13
Q

BIP, BIL, and BSQ

A
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14
Q

population

A

infinate or finite set of elements

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15
Q

sample

A

subset of the elements taken from a population used to make inferences about certain characteristics of the population

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16
Q

sampling error

A

the difference between the true value of a population characteristic and the value of that characteristic inferred from a sample

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17
Q

median

A

value midway in the frequency distribution. one-half of the area below the ditribution curve is to the right fo the median, and one-half is to the left

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18
Q

relationship between variance and standard deviation

A

The square root of variance is called the standard deviation.

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19
Q

a high kurtosis value means a high _____ compared to a normal distribution

A

peak

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20
Q

covariance

A

joint variation of two variables about their common mean

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21
Q

Kriging

A

weights the surrounding measured values to derive a prediction fro each new location

22
Q

variography

A

process whereby a spatially depended model is fit to the data and the spatial structure is quantified

23
Q

semivariance

A

provides an unbiased description of the scale and pattern of spatial variability throughout a region

24
Q

two distinct tasks involved in kriging

A
  1. quantifiying the spatial structure of the surrounding data points
  2. producing a prediction at a new location
25
standard deviation
the standard deviation is found by taking the square root of the average of the squared differences of the values from their average value
26
difference between scientific visualization and presentation graphics
The difference between scientific visualization and presentation graphics is that the latter are primarily concerned with the communication of information and results that are already understood. During scientific visualization we are seeking to understand the data and gain insight.
27
bitmapped
The digital image processing industry refers to all raster images that have a pixel brightness value at each row and column in a matrix as being bitmapped images. For example, the simplest bitmapped image is a binary image consisting of just ones (1) and zeros (0).
28
color theory used with light
additive color theory (For example, in additive color theory a pixel having RGB values of 255, 255, 255 produces a bright white pixel)
29
color theory used with pigment
subtractive color theory (mixing more pigments produces darker images)
30
optimum index factor
The largest OIF will generally have the most information (as measured by variance) with the least amount of duplication (as measured by correlation)
31
two most common types of error encountered in remotely sensed data
radiometric and geometric
32
radiometric correction attempts to...
improve the accuracy of spectral reflectance, emittance, or back-scattered measurements obtained using a remote sensing
33
geometric correction is concerned with ...
Geometric correction is concerned with placing the reflected, emitted, or back-scattered measurements or derivative products in their proper planimetric (map) location so they can be associated with other spatial information in a geographic information system (GIS) or spatial decision support system (SDSS).
34
Radiometric and geometric correction of remotely sensed data are normally referred to as
preprocessing
35
internal errors (those produced by the remote sensing system) are generally ____ in nature
systematic, predictable
36
external errors are introduced by
phenomena that vary in nature through space and time
37
three basic ways energy is transferred
conduction (one transfers its kinetic energy to another by colliding with it) convection (transfer through liquids or gasses) radiation (tranfer through a vacuum)
38
some of the sun's energy is reflected as ____ wave energy and some is absorbed and later emmitted as ____ wave energy
short, long
39
as the temperature of an object increases, its dominant wavelength...
...shifts toward the shorter wavelenths of the spectrum (thus it's possible to determine the temperature of an object based on its dominant wavelenth!)
40
wien's displacement law simplified with sun used as example
dominant wavelenth = wein's constant (2898 um K) / absolute temperature e.g. the sun's dominant wavelegth is .483 micrometers (green!) so .483 um = 2898 um K / 6000 K
41
% of sun's energy that is ultraviolet, visible, and infrared
ultraviolet = 9% visibit = 41% infrared = 50%
42
wavelength range of visible light
.4 to .7 micrometers or 400 to 700 nanometers
43
Stefan-boltzmann law
the total emitted radiation from a blackbody is proportional to the fourth power of its absolute temperature or total emmitted radiation = 5.666 x 10^-8 W m^-2 x Temperature^-4
44
4 step remote sensing process
statement of the problem data collection data-to information conversion information presentation
45
collateral data
digital elevation models soil maps surficial geology maps population density, etc
46
3 types of transformation
RGB to IHS transformation and back again Chromaticity Color Coordinates system Brovey Transformation
47
IHS stands for
intensity, hue, saturation
48
chromaticity color coordinate system
color space consisting of two independant parameters, often specified as hue and colorfulness the coordinates of the chromaticity diagram represent the relative fractions of each of the primary colors (RGB) present in a given color.
49
intensity, hue, saturation
intensity varies from black (0) to white (255) and is not associated with any color. hue represents the circumference of the sphere, which is the dominant wavelength of color saturation represents the purity of the color and ranges from 0 at the center of the color space to 255 at the circumference. a saturation of 0 represents a completely impure color which will appear as a shade of grey.
50
Brovey transform
may be used to merge (fuse) images with different spatial and spectral characteristics. It is based on the chromaticity transform and is a much simpler technique than the RGB-to-IHS transformation. The Brovey transform also can be applied to individual bands if desired. basically a resolution merge
51
Relative vs. absolute correction
Empirical line calibration can be relative or absolute. Relative correction matches 2 images. Absolute ends up with radiance values.
52