geography 12: maps and mapping - ucsbkclarke/g12/lectures/lecture23.pdf · lecture 23:...
TRANSCRIPT
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Geography 12: Maps and MappingLecture 23:
Photogrammetry and air photos for mapping
Some Definitions
• Photography: The art or process of producing images on a sensitized surface by the action of light or other radiant energy
• Image: A reproduction or imitation of the form of a view of objects
• Photo interpretation: The act of examining aerial photographs/images for the purpose of identifying objects and judging their significance
• Photogrammetry: The science or art of obtaining reliable measurements by means of photography
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1858 Photography takes to the air
• 1858 - Gasper Felix Tournachon"Nadar" takes the first aerial photograph from a captive balloon from an altitude of 1,200 feet over Paris
Wartime Advances• 1860's - Aerial observations, and possible
photography, for military purposes were acquired from balloons in the Civil War.
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Origins of Photogrammetry
• 1887 - Germans began experiments with aerial photographs and photogrammetrictechniques for measuring features and areas in forests
• 1889 - Arthur Batut take the first aerial photograph from using a kite of Labruguiere France
San Francisco1906 - George R. Lawrence
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The Great War• 1914 - Lt. Lawes, British Flying Service, takes what is thought
to be the first air photo over enemy territory in WWI• 1915 - Cameras especially designed for aerial use are being
produced. Brabazon designed and produced the first practical aerial camera
• 1918 - French aerial units developing and printing as many as 10,000 photographs each night.
• During the Meuse-Argonne offensive, 56,000 aerial prints were made and delivered to American Expeditionary Forces in four days
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Wartime technology turned elsewhere
• 1919 - Canadian Forestry Mapping Program begins• 1919 - Hoffman first to sense from an aircraft in thermal IR• 1920's First books on aerial photo interpretation begin to be
published• 1924 - Mannes and Godousky patent the first of their work of
multi-layer film which led to the marketing of Kodachrome in 1935
• 1931 - Stevens development of an IR sensitive film (B&W)• 1934 - American Society of Photogrammetry founded.
Photogrammetric Engineering first published.• 1936 - Captain Albert W. Stevens takes the first photograph of
the actual curvature of the earth - taken from a free balloon at an altitude of 72,000 feet
NHAP 1:80K (Wisconsin)
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U-2 & Francis Gary Powers
CORONA
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Photo Interpretation Tasks• Detection and identification of features, phenomena, or
processes– Detection and interpretation– Labeling– Confidence assessment
• Measurement and estimation• Use in topographic and special purpose mapping• Map update• Problem solving
– Object complexes– Object relations– Assessments/causes
• Rating of evidence– Assembly of information– Ranking and assessment
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Detection
Identification: What is it?
Source: www.mehs.educ.state.ak.us/ sitka/cross_sound.html
Sitka, Alaska
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Process
Process: Inference
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Inference: Sequence
Change detection
Bam City Japan. Digital Globe imagery Sept 03 and Jan 04 (Source: Tokyo Tech)
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Measurement
Orientation
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Spatial Resolution10cm, 25cm, 50cm, 1m
Resolution
* See mecca_saudi_arabia_quickbird_feb11_2003.tif
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Shape
Texture
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Pattern
Oblique Low Angle (no apparent horizon visible)
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Oblique Low Angle (cont.)
Oblique Low Angle (cont.)
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Overhead Vertical True
Oblique: High Angle CIR (apparent horizon visible)
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Oblique: High angle (apparent horizon visible)
Examples of High Oblique Photographs
Mozambique Flooding, March 2000
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Advantages of Vertical Aerial Photographs
• The scale is essentially constant.• Measurements of directions are easier than on
oblique photograph. Directions can also be measured more accurately.
• Within limits a vertical aerial photograph can be used as a map (if grids and marginal data are added).
• Vertical aerial photographs are often easier to interpret than oblique and are better for stereo (there is no masking).
Advantages of Oblique Aerial Photographs
• Given a constant altitude and camera you can cover a much larger area on a single photo.
• The view of some objects is more familiar to the interpreter.
• Some objects not visible on vertical photos may be seen on oblique.
• Oblique images may get results under weather
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Multi-lens mapping camera
UCSB Campus Orthophotography
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Chem Building: Nadir?
Control Point
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Motion blur
Storke Tower
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Outside Corwin
Goleta beach