1. Pictures are worth a thousand words…

2. Introduction to Remote Sensing Spatial, spectral, temporal resolutions Image display alternatives Vegetation Indices Image classifications Image change detections Accuracy assessment Satellites & Air-Photos

3. Selected RS Systems Landsat TM & Enhanced TM (Thematic Mapper) Ikonos & Quickbird MODIS (Moderate Resolution Imaging Spectrometer) Radarsat & ERS (European RS Satellite) SeaWiFS (Sea-Viewing Wide Field-of-View Sensor) GOES (Geostationary Operational Environ. Satellite) AVHRR (Advanced Very High Resolution Radiometer) SPOT (High Resolution Visible) Others

4. Digital Satellite Data Digital satellite data is one type of remotely-sensed data  aerial photography is another type of remotely-sensed geographic information Important advantage of remote sensing data:  synoptic perspective: comprehensive view of large areas of the Earth’s surface, vantage point of observation, digital format, multi- spectral, multi-temporal, multi-spatial. Remote sensing: the acquisition of data about an object or area by a sensor that is physically far from the object or area.

5. Satellite Data - Benefits & Problems Benefits:  it is already digital (unlike standard aerial photos) -- readily lends itself to manipulation and analysis to extract useful information  synoptic perspective  repeat coverage of areas  minimal scale and geometric distortion problems relative to aerial photos Problems:  generally low spatial resolution compared to aerial photos  large data storage volumes  distortions in data values due variations in atmospheric conditions, clouds, terrain, solar angle, etc... -- require preprocessing to correct!

6. Electromagnetic Spectrum (EMS) 0.40.50.60.7 Visible Portion Cosmic Gamma X-rays UV Infrared Microwave Radio/TV Rays Rays Near/Medium/Thermal Increasing Wavelength Increasing Frequency and Energy At a given Temperature, T 10 -6 10 -4 10 -2 1 10 2 10 4 10 6 10 8 Wavelength in Micrometers (= 10 3 nanometers)

8. Incoming EMR Reflected EMR Emitted EMR Passive (Optical) Sensor Technology

9. Electromagnetic Radiation Spectrum Remote sensing satellites record data on electromagnetic radiation (EMR)  satellites have detectors that record specific wavelengths in the EM spectrum EM radiation interacts with physical matter  some wavelengths are absorbed & others reflected  determine/estimate matter type by analyzing spectral “signatures” in satellite data

10. “The Four RS Resolutions” Satellite data characterized by four resolutions: spatial resolution: area on ground represented by each pixel (cell) in the satellite data. temporal resolution: how frequently a satellite platform obtains imagery of a particular area, orbital characteristics. spectral resolution: specific EM spectrum wavelength intervals captured/recorded by a particular satellite sensor. radiometric resolution: number of possible data values recorded/reportable by each satellite sensor, precision with which the EM spectral values are reported.

11. Aerial Photographs Scale = Focal Length/Flying Height Principal Point & Conjugate PP Radial Displacement Parallax Forward-Lap & Side-Lap Stereoscopic Analysis & Stereoscopes See photos for examples

19. Satellite Data - Pixel Brightness Values “Brightness Value” (BV) corresponding to intensity of EM radiation in specified spectral range detected for that pixel lower BV = lower level of EM radiation detected higher BV = higher level of EM radiation detected Displaying/viewing satellite data: high BV medium BV low BV For displaying/viewing satellite images:  high BVs assigned bright/light color value  low BVs assigned dark/dim color value

20. Satellite Data - Pixel Brightness Values & Display Landsat TM Multi-Spectral Display : +=+ Band 4 - near infraredBand 3 - red visibleBand 2 - green visible on-screen display: +=+ Band 2 - green visible Band 4 - near infraredBand 7 - middle infrared on-screen display: RED GUNGREEN GUNBLUE GUN

21. Infrared band (4) Red color gunGreen color gun Red band (3) Blue color gun Green band (2) RGB Compositing Process

22. Panchromatic Display Panchromatic display of a single band

23. Visible red (red gun), green (green gun), blue (blue gun) – “true”color Multispectral Composite Display

24. Near infrared (red gun), red (green gun), green (blue gun): “false color” Multispectral Composite Display

25. Middle infrared (red gun), near infrared (green gun), green (blue gun): “false color” Multispectral Composite Display

26. 1-2 m 30 m 79 m 1.1 km QuickBird, Landsat TM, Landsat MSS AVHRR IKONOS ETM Different Spatial Resolutions

27. Daytona 500 Racetrack February 1995, NAPP (USGS EDC) Lake Lloyd grandstands racetrack

28. Mt. St. Helens, May 1980 Aircraft photo

29. The North Pole, June 1992 AVHRR

30. The Earth at Night, DMSP mosaic

31. Kuwait Oil Fires, April 1991 Space Shuttle Smoke Plumes from Oil Fires

32. Middle East Oil Fires, November 4, 2002 MODIS

33. Thermal (Far Infrared) People

35. SeaWiFS of Europe & UK: particulate pollution in southern UK and dust cloud in southern Spain

37. GOES Image of Hurricane Bonnie August 25, 1998

38. SeaWiFS of Greenland July 15, 2000

39. Washington, DC Bands 4, 3, 2 (infrared, red, green) Landsat 7 Enhanced Thematic Mapper (ETM+)

40. GOES Image of Water Vapor: Thermal Infrared Sensing

41. SeaWiFS of Sea Surface Temperatures

42. IKONOS Multi-Spectral Imagery

43. Digital Image Data MSS 1973 TM 1999 IKONOS 1999

44. Ikonos Images & Survey Sketch