1 NAME_________________________ Remote Sensing of the Environment GEOG/GEOL 4093/5093 Spring Semester 2008 Lab Exercise #3 02/03/2008 Due: 02/10/2008 Part I: Concepts (1) Name two types of aerial cameras and discuss their difference? (2) (2) Can we use Near Infrared enhanced Black and White film to map surface temperatures? (2) (3) Indicate how effective each wavelength would be for studying the Earth’s surface from a satellite platform. Use the following terms: very good, good, ok, fair or poor. Also list the atmospheric constituent (if any) that is most responsible for attenuating each wavelength. (4) Wavelength Utility for studying the surface? Primary attenuating atmospheric gas a. 1500 nm ____________________ __________________ b. 800 nm ____________________ __________________ c. 400 nm ____________________ __________________ d. 8 mm ____________________ __________________2 (4) For each of the following attributes, indicate whether polar orbiting or geo-stationary satellites (if either) would be inherently superior? Also indicate why you made that choice. (5) a. Spatial resolution: b. Spatial coverage: c. Temporal resolution: d. Ability to study high-latitudes: e. Transmission of data to the ground: (5) Explain the term sun-synchronous orbit (what is it and why is it used?). Compare this to a geostationary orbit. How are they different and what is each used for? (3) (6) Using the absorption curves given for the filters below, how would you block the radiation less than 500 nm on panchromatic film? What reason is there for blocking these shorter wavelengths? (2)3 Part II: Landsat TM imagery and color composites Launch Internet Explorer and type \\nyx\rs4093 into address bar and hit enter, that takes you to the remote sensing class folder “rs4093” in CIRES server. Copy the folder “Lab_3” to “C:” drive. Launch ENVI. Open the image file “C:\lab_3\bo_tm_bsq.512x512x7.img”. This image contains all 7 bands of a Landsat TM image of Boulder. In the Available Bands List window, select “RGB Color”. Assign Band 4 to R (red), Band 3 to G (green) and Band 2 to B (blue). Click Load RGB. This will create and display what is known as a “False-color composite image.” These images are often used in image analysis. (7) What features stand out in this false-color composite? What colors do these features appear? (Choose at least 3 different land-cover types to describe). (3)4 (8) What portions of the electromagnetic spectrum are mapped to which colors? (Be specific.) (3) Play around with various band combinations and try to create a “true-color” image. Note that satellites do not take pictures of the ground so you cannot create an image that will look like a photograph, but using some clever color mapping you can create an image that looks as close to a photograph as possible. (9) What bands did you use to create a “true-color” image? Which colors did you map these to? Why do these bands work? (Be specific about spectral regions.) (4) Band 6 of Landsat TM is a thermal band. Unlike the other 6 bands that have a 30 m pixel size, the thermal band has a 120 m pixel size. Display Band 6 in gray scale. (10) What features are lost at this resolution? What features are still apparent?
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