BOT/GEOG 4111/5111
Fall 2015
The final exam is partly comprehensive, but the emphasis will be on material that we
have covered since the last midterm exam. This review sheet includes material from the full semester that you should be familiar with (the comprehensive part). The final exam format will be the same as for the two midterms. There will be more questions on the new material than on the old. Be sure to bring a calculator.
Old Material (from entire semester)
Reflectance
1. Be able to draw typical reflectance curves for vegetation, soil, and water.
2. Know what properties of vegetation control the 3 parts of the vegetation reflectance curves.
3. Know how adding layers of leaves affects the vegetation reflectance curve.
Resolution
1. Be able to define the 4 types of resolution we discussed (spatial, spectral, radiometric, temporal).
2. Understand the relationship between signal to noise ratio (SNR) and resolution.
3. Be able to calculate the number of pixels of known spatial resolution in a given area.
Radiometric Correction
1. Be able to define path radiance.
2. Understand when and why you might need to do atmospheric correction.
Vegetation Indices
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1. Be able to draw and interpret a red-NIR feature space and show where vegetation and soil are located in the data cloud.
2. Know the 3 things a good vegetation index should do.
3. Be able to create a spectral or temporal index, given graphs of spectral or temporal properties.
Classification
1. What is a classification scheme, and what are the guidelines that a good scheme must satisfy?
2. Understand the difference between supervised and unsupervised classification.
3. Know what spectral confusion is, and be able to discuss methods for dealing with it in classification.
New Material (since last midterm)
Accuracy Assessment
1.
What is thematic accuracy? What is spatial accuracy?
2.
What is the difference between accuracy and precision?
3.
What are the basic steps for performing thematic accuracy assessment?
4.
What are the characteristics of a good sampling scheme for accuracy assessment?
5.
How large should a sample site in the field be for collecting reference data for accuracy assessment?
6.
What is double sampling? Be able to describe how it works.
7.
What is a contingency table (= error matrix)? Be able to construct one.
8.
Be able to define and calculate all of the confusing terms we talked about: errors of omission, errors of commission, user’s accuracy, producer’s accuracy and overall accuracy. You do NOT have to calculate the Kappa statistic.
9.
What is the Kappa Statistic (define)? Why is it meaningful?
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10.
Why are the off-diagonal elements in a contingency table so important?
Field Data Collection and GPS
1.
What are the main difference between recreational, mapping, and survey grade
GPS?
2.
What are the differences between simple random, stratified random, and systematic sampling schemes? Which is used most frequently for remote sensing accuracy assessment and why?
3.
What is trilateration?
Change Detection
1.
What is change detection? Be able to describe some applications of change detection mapping.
2.
What two aspects of change do we try to measure when we do change detection analysis?
3.
Be able to describe how each of the change detection methods we discussed works: a.
Image algebra (differencing and ratios) b.
Post classification comparison c.
Multi-date composites d.
Change vector analysis e.
Image display
4.
What is a transition matrix? How is it used? Be able to interpret a transition matrix.
5.
What issues must be considered when using multi-date imagery to map change detection?
Active Remote Sensing
Radar
1.
What is the difference between passive remote sensing and active remote sensing? What does the acronym “RADAR” stand for?
2.
What wavelength region (general name) is used by radar systems? What are some advantages that these wavelengths provide?
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3.
What do we mean by side looking radar? Why is side looking radar an advantage for ground imaging?
4.
Be able to define and/or illustrate the terms range, azimuth, backscatter, and depression angle.
5.
Explain what we mean by polarization. What ground characteristics tend to depolarize (or cross polarize) radiation from radar? How can we use radar polarity to interpret ground features?
6.
Why do smooth surfaces typically look dark in a radar image and rough surfaces bright?
7.
What is a corner reflector?
8.
Why is radar useful for discerning forest structure? Which wavelengths (shorter or longer?) typically penetrate the leaves and twigs? Which bounce off the leaves and twigs?
9.
Describe in general terms why the Doppler Effect is important for achieving higher spatial resolution in radar than would otherwise be possible.
10.
What are some applications of radar imaging?
Lidar
11.
What wavelength region(s) does Lidar typically use?
12.
Be able to describe two typical Lidar applications.
Thermal Remote Sensing
1.
What general wavelength range do we use for thermal remote sensing? Why are “atmospheric windows” important for these wavelengths?
2.
What is emissivity? What common material on the earth’s surface has emissivity close to 1.0? What is the emissivity of plants (approximately)?
3.
Be able to define kinetic temperature and radiant temperature. Which do we measure with thermal remote sensing? How does emissivity play a role in the latter?
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4.
What facts do you need to know about a thermal image before you start interpreting it? Why?
5.
List some of the factors that complicate the interpretation of thermal imagery.
6.
Why do thermal sensors typically have lower spatial resolution than sensors that measure shorter wave reflected radiation (like visible or NIR)?
7.
When you display 3 bands of a thermal image as red, green, and blue, why does the result often appear to be monochrome (black and white).
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