Compilation in digital form of data previously presented in analog forms such as contours on paper maps, plots, or other graphical materials, so that the digital data produced approximates the scientific measurements used to create the original printed materials.
This category is also used for digitizing.

Results listed by similarity [list alphabetically]
Prospect- and mine-related features on USGS topographic maps

Symbols indicating mining-related features digitized from historical USGS topographic maps in the western part of the conterminous US. Includes prospect pits, mine shafts and adits, quarries, open-pit mines, tailings piles and ponds, gravel and borrow pit