Digital Orthophoto Quadrangles Provide Greater Detail
This image comes from Grant County, Nebraska just south of the town of Hyannis. This location was depicted in the Landsat 7 image on the previous page. In that image it is located in the right center on a line extending straight north of the eastern end of Lake McConaughy and about halfway up the image. I obtained this panchromatic image from a website data bank managed by the Nebraska Conservation and Survey Division. It is an image obtained from the National Aerial Photography Program (NAPP). This is a 3.5 minute Digital Orthophoto Quarter Quadrangle. The scale is 1:12,000 and resolution is 1 meter. NAPP photos are usually taken at about 20,000 feet above land surface.
In the satellitte image these dunes appear fairly linear from east to west. This photo depicts more detail and one sees the southerly points where the horns of the barchan dunes have grown together to form barchanoid-ridge dunes.
Smaller linear dunes running more north to south are visible atop the barchanoid-ridge dunes. According to H.T.U. Smith these were probably formed in the second episode of dune formation.
Note the flood-irrigated hay fields in the interdunal zones. If one zooms in, the irrigation canals and borders are even visible. Small lakes abound in the Sand Hills which explains why this region is in the North American flyway for migratory birds.
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