Data Type:  Digital Orthophotoquad (DOQ) - computer-readable high
  
resolution images derived from aerial photographs, corrected to
  
remove the displacements of perspective, camera tilt, and 
  
terrain relief.


Coordinate Reference:  NH State Plane feet, NAD83


Resolution: 1 meter

Format:  compressed, geo-referenced .sid images




The above files were derived from standard USGS DOQs, processed as follows:


  -convert image to grid (ARC imagegrid command)

   -project grid from UTM meters (zone 18 or 19), NAD83, to NH State Plane 

    feet (zone 4676), NAD83
  
   -convert grid to tiff image (ARC gridimage command with no compression)
   -convert tiff image to a geo-referenced MrSID with a 1:20 encoding ratio



See "http://mapping.usgs.gov/www/html/2nmpgds.html" for standards

used to generate the source USGS product.