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GEO 4120c Workshop 16 February 2009 |
Introduction
Binocular vision allows
us to achieve three-dimensional (3-D) effects. We view objects from two
slightly different perspectives simultaneously, and our brain processes
the parallax distortion as depth. Aerial photographs that overlap give
us the two slightly different perspectives and can be viewed with
stereoscopes to produce 3-D effects. This gives the analyst the ability
to view topography and measure heights. Stereo-pair analysis is one of
the most useful functions in air photo interpretation.
Sources of
imagery in this exercise: Handouts, Arnold, Wanless, Private Collection
Exercise:
1. Practice achieving
stereovision: Answer the following questions:
Within the rings marked 1 through 8 are designs that appear to be at different elevations. Using "1" to designate the highest elevation, write down the depth order of the designs. It is possible that two or more designs may be at the same elevation. In this case, use the same number for all designs at the same elevation.
Ring 1 (Done for you as an example) Ring 6
Square (2) Lower left circle ( )
Marginal ring (1) Lower right circle ( )
Triangle (3) Upper right circle ( )
Point (4) Upper left circle ( )
Marginal ring ( )
Ring 7
Black flag with ball ( ) Ring 3
Marginal ring ( ) Square ( )
Black circle ( ) Marginal ring ( )
Arrow ( ) Cross ( )
Tower with cross ( ) Lower left circle ( )
Double cross ( )
Black triangle ( )
Black rectangle ( )
Indicate the relative elevations of the rings 1 through 8
Highest ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) Lowest
NOTE FOR 2010: THIS SECTION WAS NOT WELL DONE BY THE STUDENTS. HAVE SOMETHING IN THE LECTURE ABOUT HOW TO INTERPRET AND DESCRIBE A LANDSCAPE.
For the following questions that ask for descriptions, answer in your own words, not in words from the captions of the aerial stereograms. Be brief, but be informative in your interpretation. Write what you would see in terms of morphology (shape), vegetation, water, and any other features that you can interpret from the photograph.
2. In Wanless Plate 4, How many actual sinkholes are shown in the stereogram in the zone of optical overlap?
3. Wanless Plate 5: Describe briefly what it would be like to walk through this landscape from a point at D-4.5 to C-4.0? Be somewhat comprehensive (although brief) and write a description that would tell someone else what they could expect to encounter along the way.
4. Wanless Plate 9: Where is the highest point in the stereo-overlap section this stereogram? The lowest point?
5. Wanless Plate 10: Describe the morphology of the contact between the glacier and the valley wall.
6. Wanless Plate 14: Which side of Sue Lake has the steepest slope? Cirque lakes are found in formerly glaciated valleys. Which direction did the glacier flow (assume that North is up - in the Y axis of the stereotriplets).
7. Wanless Plate 20: What is a drumlin? Which direction was the glacier flowing (according to the interpretation of the text)? Assume that north is in the 1-4 direction and east is the A-D direction. Be specific with your direction (e.g. northwest, south, etc.).
8. Wanless Plate 25: Where is the highest point, the lowest point, and which way does water generally flow in this landscape?
9. Wanless Plate 28: You have all had Physical Geography or equivalent. Is this coast an emergent or submergent coastline? What features do you see in this image to give you the clues to decide?
10. Wanless Plate 31: Here we are in the Florida Panhandle. The text says that the succession of beach ridges is indicated by light tone, while the swales are dark. Why are these colors diagnostic of ridge-swale patterns, and what ecological processes do you think causes the patterns?
Within the rings marked 1 through 8 are designs that appear to be at different elevations. Using "1" to designate the highest elevation, write down the depth order of the designs. It is possible that two or more designs may be at the same elevation. In this case, use the same number for all designs at the same elevation.
Ring 1 (Done for you as an example) Ring 6
Square (2) Lower left circle ( )
Marginal ring (1) Lower right circle ( )
Triangle (3) Upper right circle ( )
Point (4) Upper left circle ( )
Marginal ring ( )
Ring 7
Black flag with ball ( ) Ring 3
Marginal ring ( ) Square ( )
Black circle ( ) Marginal ring ( )
Arrow ( ) Cross ( )
Tower with cross ( ) Lower left circle ( )
Double cross ( )
Black triangle ( )
Black rectangle ( )
Indicate the relative elevations of the rings 1 through 8
Highest ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) Lowest
NOTE FOR 2010: THIS SECTION WAS NOT WELL DONE BY THE STUDENTS. HAVE SOMETHING IN THE LECTURE ABOUT HOW TO INTERPRET AND DESCRIBE A LANDSCAPE.
For the following questions that ask for descriptions, answer in your own words, not in words from the captions of the aerial stereograms. Be brief, but be informative in your interpretation. Write what you would see in terms of morphology (shape), vegetation, water, and any other features that you can interpret from the photograph.
2. In Wanless Plate 4, How many actual sinkholes are shown in the stereogram in the zone of optical overlap?
3. Wanless Plate 5: Describe briefly what it would be like to walk through this landscape from a point at D-4.5 to C-4.0? Be somewhat comprehensive (although brief) and write a description that would tell someone else what they could expect to encounter along the way.
4. Wanless Plate 9: Where is the highest point in the stereo-overlap section this stereogram? The lowest point?
5. Wanless Plate 10: Describe the morphology of the contact between the glacier and the valley wall.
6. Wanless Plate 14: Which side of Sue Lake has the steepest slope? Cirque lakes are found in formerly glaciated valleys. Which direction did the glacier flow (assume that North is up - in the Y axis of the stereotriplets).
7. Wanless Plate 20: What is a drumlin? Which direction was the glacier flowing (according to the interpretation of the text)? Assume that north is in the 1-4 direction and east is the A-D direction. Be specific with your direction (e.g. northwest, south, etc.).
8. Wanless Plate 25: Where is the highest point, the lowest point, and which way does water generally flow in this landscape?
9. Wanless Plate 28: You have all had Physical Geography or equivalent. Is this coast an emergent or submergent coastline? What features do you see in this image to give you the clues to decide?
10. Wanless Plate 31: Here we are in the Florida Panhandle. The text says that the succession of beach ridges is indicated by light tone, while the swales are dark. Why are these colors diagnostic of ridge-swale patterns, and what ecological processes do you think causes the patterns?
Turn in to G:\share\GIS 4120c
Air Photo Interepretation\yourname\,
email to mbinford@geog.ufl.edu, or hand in as a printed copy.