Source
The NED dataset is a compilation of data from a variety of existing high-precision datasets such as LiDAR data (see also National LIDAR Dataset - USA), contour maps, USGS DEM collection, SRTM and other sources which were reorganized and combined into a seamless dataset, designed to cover all the United States territory in its continuity.
Read more about this topic: National Elevation Dataset
Famous quotes containing the word source:
“The source of our actions resides in an unconscious propensity to regard ourselves as the center, the cause, and the conclusion of time. Our reflexes and our pride transform into a planet the parcel of flesh and consciousness we are.”
—E.M. Cioran (b. 1911)
“If all else perished, and he remained, I should still continue to be; and if all else remained, and he were annihilated, the universe would turn to a mighty stranger. I should not seem a part of it.... My love for Heathcliff resembles the eternal rocks beneath—a source of little visible delight, but necessary. Nelly, I am Heathcliff—he’s always, always in my mind—not as a pleasure, any more than I am always a pleasure to myself—but as my own being.”
—Emily Brontë (1818–1848)
“We are threatened with suffering from three directions: from our own body, which is doomed to decay and dissolution and which cannot even do without pain and anxiety as warning signals; from the external world, which may rage against us with overwhelming and merciless forces of destruction; and finally from our relations to other men. The suffering which comes from this last source is perhaps more painful than any other.”
—Sigmund Freud (1856–1939)