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Remote Sensing GIS/Remote Sensing Workshop June 6, 2013.

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Presentation on theme: "Remote Sensing GIS/Remote Sensing Workshop June 6, 2013."— Presentation transcript:

1 Remote Sensing GIS/Remote Sensing Workshop June 6, 2013

2 Outline What is remote sensing? How do we practice remote sensing? Why do we use remote sensing? Have you done remote sensing before?

3 What is Remote Sensing? “The art and science of obtaining information about an object without being in direct contact with the object” (Jensen, 2000)

4 Remote Sensing of the Environment Observe the world through remote sensing Use technology to surpass the limits of the human eye Courtesy: earthobservatory.nasa.gov

5 How does remote sensing work? Electromagnetic Spectrum Courtesy: science.hq.nasa.gov

6 Use of Electromagnetic Radiation Courtesy: missionscience.nasa.gov, science.nasa.gov Emission Reflection Radiation

7 Types of Remote Sensing and Technology Passive The sensor receives and measures incoming radiation Ex: Film photography, IR photography Active Send out radiation and measure how much is reflected back to the sensor or how long it takes to return Ex: Radar, Lidar AerialPhotos LiDAR Radar Satellite Imagery ACTIVE PASSIVE

8 Brief History of Aerial and Satellite Imagery 1850s: Flight WW1 and WW2:Aerial Surveillance and Reconnaissance Post-WW2: Civilian Applications 1960: Space Age RS 2000: Public Remote Sensing

9 Image Basics Composed of pixels “picture elements” Smallest unit in an image, single- colored Sensor records electromagnetic radiation within the pixel’s area Cameras 3 Megapixels = 3,000,000 pixels 10 Megapixels = 10,000,000 pixels Courtesy: earthobservatory.nasa.gov

10 Resolution Spatial Size of the smallest feature that the sensor can detect Refers to “pixel size” Worse resolution = Lower resolution Courtesy: Jim Campbell, Introduction to Remote Sensing; USGS

11 Resolution Temporal Length of time between sensor visits Spectral Size of wavelength interval that the sensor can distinguish March 2002 June 2002 Courtesy: NASA

12 Visualizing a Pixel Lab

13 Aerial Photography vs. Satellite Imagery Standard aerial imagery is RGB Color infrared photography records IR reflectance Satellite imagery is a digital composite of many images taken at the same place and time, each at a different wavelength Red Green Blue IR ? Courtesy: NASA

14 Display of Colors in Satellite Images The computer displays images in 3 colors: Red, Green, and Blue. Every computer graphic contains a combination of these colors to include the entire visible spectrum. Satellite images contain much more information! How would you display non-visible radiation on a computer screen or in a photo? For example, what color would you make IR? Image users decide which wavelengths to display

15 Digital Pixels Analyst selects and combines 3 of the wavelengths for RGB color image Sensor records the image reflectance for each wavelength Red Blue Green NIR I NIR 2 NIR 3

16 False Color Images

17 Image Interpretation Clues Location Size Color Texture Shape Pattern Height/Depth Site Association Courtesy: earthobservatory.nasa.gov Texture

18 Image Interpretation Courtesy: USGS

19 Image Interpretation Lab

20 Why do we use remote sensing? Agriculture, Forestry, Range GovernmentGeologyWater Resources ArchaeologyEnvironment Vegetation types Land useRock typesWater boundaries Ancient ruins and roads Disaster damage Crop areaRegional Planning Geologic units Floods and floodplains Non-invasive records Mining and reclamation BiomassMappingLandformsGlaciers/IcePollution Veg healthTransportation planning Water depthWildlife distributions Soil conditions Turbidity and circulation Adapted from “The Landsat Tutorial Workbook” (NASA, 1982)

21 Worldwide Applications Courtesy: eros.usgs.gov


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