Data Type:  Digital Orhophoquad (DOQ) - computer-readable high
  resolution images derived from aerial photographs, correct 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 .tiff 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 using tiff compression)

See "http://mapping.usgs.gov/www/html/2nmpgds.html" for standards
used to generate the source USGS product.