U. S. Geological Survey Mapping in the 20th Century

1905 -- USGS Topographic Map of Detroit, Michigan - The U.S. Geological Survey (USGS) produced its first topographic map in 1879, the same year it was established. Today, more than 100 years and millions of map copies later, topographic mapping is still a central activity for the USGS. The topographic map remains an indispensable tool for government, science, industry, and leisure.

1914 -- USGS Topographic Map of Oregon City, Oregon - The National Mapping Program of the USGS is the descendant of the Corps of Topographical Engineers, formed in 1838 to map the western lands of the then conterminous United States.

1958 -- USGS Topographic Map of Milwaukee, Wisconsin - The best known of today's USGS maps are the 1:24,000-scale topographic maps, also known as 7.5-minute quadrangles. The USGS began mapping the country at this scale after World War II and completed the program in the late 1980's.

1970's -- Landsat Program - In the mid-1960's, the National Aeronautics and Space Administration (NASA) embarked on an initiative to develop and launch the first Earth-monitoring satellite to meet the needs of resource managers and earth scientists. The U.S. Geological Survey entered into a partnership with NASA in the early 1970's to assume responsibility for archiving data and distributing data products. On July 23, 1972, NASA launched the first in a series of satellites designed to provide repetitive global coverage of the Earth's land masses.

1980's -- Digital Line Graphs - Digital line graph (DLG) data are digital representations of cartographic information. DLG's of map features are digital vectors converted from maps and related sources.

1980's -- Digital Elevation Models (PDF) - Digital elevation model (DEM) data are arrays of regularly spaced elevation values referenced horizontally either to a Universal Transverse Mercator (UTM) projection or to a geographic coordinate system. The grid cells are spaced at regular intervals along south to north profiles that are ordered from west to east. The USGS produces five primary types of elevation data: 7.5-minute DEM, 30-minute DEM, 1-degree DEM, 7.5-minute Alaska DEM, and 15-minute Alaska DEM.

1980’s -- Digital Orthophoto Quadrangles - A digital orthophoto quadrangle (DOQ) is a computer-generated image of an aerial photograph in which image displacement caused by terrain relief and camera tilts has been removed. It combines the image characteristics of a photograph with the geometric qualities of a map.