Originator: Complex Systems Research Center, University of New Hampshire
The data set contains 1:12,000-scale, 1-meter resolution,
black & white orthophotoquads, compressed from TIFFs to
Orthophotos combine the image characteristics of a
photograph with the geometric qualities of a map. The
primary digital orthophotoquad (DOQ) is a 1-meter ground
resolution, quarter-quadrangle (3.75-minutes of latitude by
3.75-minutes of longitude) image. The geographic extent of
the DOQ is equivalent to a standard quarter-quadrangle.
The normal orientation of data is by lines (rows) and
samples (columns). Each line contains a series of pixels
ordered from west to east with the order of the lines
from north to south. The radiometric image brightness
values are stored as 256 gray levels ranging from 0 to 255.
While the original USGS format for distribution of DOQs
is TIFF images, GRANIT distributes the data in both
MrSID and the original TIFF formats.
The metadata record provided with the DOQ contains
a wide range of descriptive information including format
source information, production instrumentation and dates,
and data to assist with displaying and georeferencing the
image. In addition to this file, the original USGS header
file, including source and coordination information, is
available upon request. However, please note that it will
not reflect processing completed at Complex Systems Research
Center (see DATA_QUALITY_INFORMATION below).
Theme Keywords: DOQ, DOQQ, digital orthophoto, digital orthophotoquad, digital image map, aerial photograph, rectified photograph, rectified image, orthophoto, quarter-quadrangle orthophoto, 1-meter orthophoto, 3.75- x 3.75-minute orthophoto, 7.5- x 7.5-minute orthophoto