EAS 221

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  1. GIS
    Geographic information system: integrates hardware, software, and data for capturing, managing, and displaying all forms of geographically referenced information
  2. Raster
    Grid. Cells that each have a state/contain information
  3. Vector
    Point, line, polygon. Gives us just what we want (like lines on a map representing roads)
  4. Attribute
    Non-spatial data. Attributable and assigned to spatial locations (ex. names, populations attached to any point).
  5. Geographic
    Earth's surface and near-surface
  6. Spatial
    Any space (including geographic) ex. medical imaging
  7. First GIS
    Canada Land Inventory (1960)
  8. Landsat 1 (ERS-1)
    Launched in 1972, first orbital satellite that was designed for environmental studies
  9. Remote Sensing
    • Gathering of data about the earth and environment by satellite sensors
    • Using information that's contained in the electromagnetic radiation reflected from an object
  10. Scene
    Volume of area, object of interest
  11. Temporal Resolution
    Orbital characteristics; how often a certain satellite revisits a certain location
  12. radiometric resolution
    the fineness of the chunks of waves a sensor can identify
  13. spatial resolution
    • pixel size, ex. digital camera resolution
    • the more pixel resolution, the more detailed
  14. active sensors
    sensor itself provides the energy initially needed as well as receiving
  15. Passive sensors
    relies on the sun as the source for electromagnetic radiation
  16. metadata
    data about the data (so meta)
  17. Image resolution
    resolution quantifies how close lines can be to each other and still be visibly resolved
  18. Types of imaging systems in remote sensing
    • frame
    • scanner
    • pushbroom
    • whiskbroom
  19. IFOV
    instantaneous field of view, area of the ground viewed at one spot
  20. endmember spectra
    examples of the spectra from the pure individual elements within a pixel
  21. vertical aerial photography
    • determination of distances, areas, and directions
    • importance of precise height and attitude(?) information
  22. Wavelength
    distance from one peak to the next
  23. frequency
    number of peaks passing a fixed point over a period of time
  24. amplitude
    height of each peak (related to energy and brightness)
  25. velocity of light (c) =
    frequency (v) x wavelength (lambda)
  26. Visible light spectrum wavelengths
  27. Blackbody radiation
    • "perfect absorber" (also perfect emitter)
    • all materials emit radiation at a given temp and frequency exactly as well as it absorbs the same radiation
  28. the blackbody spectrum
    the shape of the blackbody radiation curve is the same at all temperatures
  29. The dividing line b/w reflected and emitted IR wavelengths is about _____
    3um (3000nm)
  30. Reflection
    when a ray of light is redirected as it strikes a surface
  31. specular reflection
    surface is smooth relative to the wavelength
  32. diffusive reflection
    when the surface is rough relative to the wavelength
  33. Raleigh scattering
    particles are smaller than wavelength of light, more scattering, more absorbance
  34. Mie scattering
    particles are about same size as wavelength of light, similar amount of each wavelengths comes through (whiteness of clouds)
  35. Non-selective scattering
    particles are bigger than the wavelengths of light, lets us see dark things like smog, smoke, etc.
  36. Absorption band
    range of wavelengths in the EM spectrum in which radiant energy is absorbed by a substance
  37. Close-downs
    regions of the spectrum in which the atmosphere is absorbing all the EM energy are not visible from space
  38. Windows
    regions of the EM spectrum where the atmosphere is absorbing little or not at all. EM energy can be used to observe the surface of the earth.
  39. Radiance
    Information received by sensor (in watts per square meter per steradian)
  40. reflectance
    ratio of reflected versus incoming radiant flux (ex. brighter a surface the higher its reflectance)
  41. Registration
    Making two image layers correspond (same scale, making sure they line up)
  42. Georeferencing
    • Process of assigning map coordinates to image data¬†
    • Giving it spatial coordinates
  43. Orthorectification
    3D terrain correction
  44. 2-step process of rectifying geometric distortions and projecting the data onto a 2D plane
    • 1. Rectification
    • 2. Resampling
  45. GCP
    Ground control points: x, y coordinates of known locations
  46. Nearest Neighbour
    Assigns a pixel value based on nearest pixel in original matrix to a given pixel in the output matrix
  47. Bilinear interpolation
    assigns a value based on a weighted linear average of the 4 nearest pixels in the original matrix
  48. Cubic Convolution
    Assigns a value to a given cell in the output matrix based on a 4x4 moving average calculated using a cubic polynomial
  49. DN
    digital number
  50. Spectral Resolution
    a measure of the ability of a spectrometer to resolve features in the electromagnetic spectrum
  51. Spectral bands
    the regions (bands) of the EMR that are detected by the sensor
  52. Multispectral sensors
    Characterized by relatively small number of spectral bands (<30)
  53. Hyperspectral sensors
    Characterized by hundreds of narrow spectral bands (>200)
  54. Radiometric Resolution
    • The sensitivity of a sensor to differences in signal strength/radiance
    • the number of gray tones in a range
  55. Geostationary orbit
    • Seem stationary above earth because they revolve with the same speed as the earth over the equator
    • ex. weather satellites¬†
    • can get as high a temporal resolution as you want
  56. Polar orbit
    • Move North-South and pass close to poles
    • only record data in the ascending pass (moving northward)
  57. Sun-synchronous orbit
    • Polar orbit that covers each area of the world at a constant local time of day called sun time
    • always in light
    • can collect data 24/7
  58. Supervised Classification
    • Identifying spectrally similar areas on an image by identifying "training" sites of known targets, then using those spectral signatures to classify other areas of unknown targets
    • (need previous knowledge of area for this)
  59. Unsupervised Classification
    Categorization of digital image data based solely on the image statistics w/out availability of training sites, no prior knowledge of the area
  60. Image classification
    Grouping image pixels from different spectral bands into categories or classes
  61. NDVI
    Normalized Difference Vegetation Index
  62. Absorption =
    incoming radiation - (reflection + transmission)
  63. Important plant pigments
    Chlorophyll a and b, carotenoids,
  64. State Change: Compositing
    ex. takes vegetation index data from 3yrs of forest fire data
  65. Delta Classification
    Following actual classification
  66. Spectronomics
    Spectral mapping of taxonomic diversity
  67. Remote sensing of the atmosphere: most important variables
    • Clouds
    • Humidity
    • Precipitation
    • Aerosols
  68. Higher clouds are _______
  69. GOES
    Geostationary Operational Environmental Satellite
  70. AVHRR
    Advanced Very High Resolution Radiometer
  71. LiDAR
    • Light Detection and Ranging
    • wavelengths of 400-1500nm
  72. Cloudsat
    • Cloud profiling radar CPR
    • Uses microwaves

Card Set Information

EAS 221
2014-10-05 19:59:05
GIS remote sensing

Intro to GIS and remote sensing
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