Satellite / Aerial Images

Sections

• Geospecific Imagery:
  • File Formats
  • Satellite
    • Processing Satellite Images
  • Aerial
    • Collecting Your Own Aerials
  • Free Sources and Directories of Imagery
  • Commercial Sources
• Geotypical Imagery
• Whole-Earth Images

Terminology

• "band"
  • refers to an image which represents a certain range of the electromagnetic spectrum, e.g. the "Red band"
• "panchromatic"
  • a monochromatic image - shades of grey (greyscale) from black to white, which generally covers a wide part of the spectrum, hence "pan"
• "multispectral" means color information, but usually not visible light spectrum
  • when these bands, which include non-visible light, are combined, the result is a "false color" image
  • common bands: red, green, infrared
  • sometimes abbreviated to MSS
• "geospecific" means a texture that represents what the ground actually looks like in a specific location
  • e.g.. an aerial photo
• "geotypical" means a generic texture
  • e.g. "grass" which is used for any grassy area

• aerial images are usually either visible light or infrared
• satellite images are usually not visible light, since the visible spectrum (especially blue) does not travel well into space

Cell Registration

• is it good to know the cell registration of an image, though nearly all images rasters are supplied with data extents which are based on the corners of each pixel