1. More Remote Sensing Today- - announcements - Review of few concepts - Measurements from imagery - Satellites and Scanners

2. ► http://ngs.woc.noaa.gov/katrina/ http://ngs.woc.noaa.gov/katrina/

3. Announcements ► Should read chapter 6 for Thursday. Not on Syllabus! ► Bring rulers to class on Thursday… if you got one.

4. Last lecture we talked about… ► Remote sensing ► Map interpretation ► Geographical data acquisition, management, and analysis ► Introduction to Geographic Information Systems ► Map production

5. Remote Sensing ► …is the gathering of information by means of a sensor that is not in contact with the object being detected.

6. Nature of EM radiation

7. Atmospheric windows

8. Remote Sensing ► Types of sensors  Active  Passive

9. Remote Sensing ► See page 254 in Campbell  Film ► Panchromatic ► Color ► False Color IR  Sensors ► Narrow-band ► Multispectral devices

10. Remote Sensing ► How the image is taken..  Vertical  High-oblique (with horizon)  Low-oblique (without horizon)

11. Remote Sensing ► vertical

12. Remote Sensing ► oblique

13. Remote Sensing ► oblique

14. Remote Sensing ► Why use obliques??

15. Remote Sensing ► Why use obliques??

16. Remote Sensing ► Summary of a few things…  Remote sensing instruments can be divided in many different ways… ► Active / passive ► Film / sensor ► Narrow band / multispectral ► Angle of photo / scan

17. Remote Sensing ► Aerial Photos…  how they are made… p. 258  Planimetric Shift… p. 260

18. OK, so… some new stuff… ► Scale…..  Large and small

19. Scale ► Large scale is local ► Small scale is global

23. Scale ► Word scales ► Representative fraction ► Graphic

25. Scale ► 1:24,000 topos ► Brits do word scale.. 1 inch represents one mile A.K.A. 1 : 63,360

26. Graphic scale

27. Finding scale on an image ► Find something on photo with a known size ► Compare to a map or other photo with a known scale.

29. Measuring stuff on an image - Photogrammetry - ► Linear  Dimensional analysis

31. Measuring stuff on an image - Photogrammetry - ► Linear  Dimensional analysis ► Area

33. Measuring stuff on an image - Photogrammetry - ► But what if they are squiggly features??? ► Linear  Dimensional analysis ► Area

35. Measuring stuff on an image - Photogrammetry - ► Linear  Dimensional analysis ► Area ► Height  Shadows  Planimetric shift

37. See photo in Remote Sensing book ► Video projector

38. Measuring stuff on an image - Photogrammetry – ► What about the effects of mountains and terrain on measurements?? ► Linear  Dimensional analysis ► Area ► Height  Shadows  Planimetric shift

39. Scanners and satellite imagery ► How scanners work…. As opposed to photos ► Pixels ► Often 256 values 0 – 255 levels of detection ► Multispectral  Bands covered… 3 in visible, near IR and Far IR  Also radar and microwave (active systems)

40. ► A brief history of satellites ► 1972 Landsat.  1-4 no longer work, 6 bit it. 5 and 7 still working  Cover same spot on earth about every 16 days  “Whisk broom scanner”  Multispectral scanner and thematic mapper Start here….. Scanners and satellite imagery

41. Scanners and satellite imagery ► Multispectral scanner  79 by 79 resolution  See page 272 (top) for bands covered

42. ► The MSS can simulate rather crude spectral signatures. Bands 4, 5, and 6 each have a bandwidth of 0.1 µm; and band 7's width is 0.3 µm. We represent band responses by bars in a histogram-like plot, in which the height of the bar signifies the relative reflectances averaged for all wavelengths within the bandwidth interval.. From…http://rst.gsfc.nasa.gov/Intro/Part2_18.html

44. From http://www.grid.unep.ch/proser /remotesens/iraq.php. Landsat image: MSS Bands 4, 2 and 1, taken on 16 February 1973, 14 February 1975 and 27 May 1976. http://www.grid.unep.ch/proser /remotesens/iraq.php http://www.grid.unep.ch/proser /remotesens/iraq.php

45. Scanners and satellite imagery ► Multispectral scanner  79 by 79 resolution  See page 272 (top) for bands covered ► thematic mapper  30 x 30 resolution (thermal – 120 or 60)  See page 273 for bands covered

46. Scanners and satellite imagery ► Resolution  Object needs to be 2x resolution to be seen (reliably)

47. ► From http://www.grid.unep. ch/proser/remotesens/ iraq.php. Landsat image: ETM Bands 4, 3 and 2, taken on 26 March and 4 May 2000. http://www.grid.unep. ch/proser/remotesens/ iraq.php http://www.grid.unep. ch/proser/remotesens/ iraq.php

51. Atmospheric windows

53. ► TM image ► Bands 2, 3, 4 ► Displayed blue, green, red

54. ► 25-Meter MultispectraL, Landsat TM, Bands 7,4,3 (RGB), Acquired February 13, 1989. In this image of Hong Kong, vegetation appears in green, bare soil is reddish purple, and urban features are purple and white. This particular band combination easily distinguishes water/land boundaries because water bodies (shown in black) contrast strongly with colorful land features. ► From http://landsat.gsfc.nasa. gov/images/gallery.html

55. ► http://www.siskiyous.edu/shasta/map/sat/

56. Scanners and satellite imagery ► SPOT  ‘push-broom’ scanner  3 visible and near IR  20 meter multispect and 10 meter single  Fly-over same spot each 20 days (apx)  Can be pointed away from vertical. Uses? ► Stereopairs, more frequent observations

57. Scanners and satellite imagery ► IKONOS  1 meter (page 274 in book) ► Active  Radar and microwave ► Military  ??????

58. Scanners and satellite imagery ► Contrast stretching and edge enhancement (page. 276)

59. To Summarize……

60. Remote Sensing ► Summary of a few things…  Remote sensing instruments can be divided in many different ways… ► Active / passive ► Film / sensor ► Narrow band / multispectral ► Angle of photo / scan

61. Photogrammetry ► Summary  Scale  Measurements, linear, area, height  Dimensional analysis  Effects of topography

62. Scanners and satellite imagery ► Summary  Pixels and scanners  MSS, TM, SPOT, etc  Resolution  Bands  ‘false color’  Comparisons  Image enhancement