7 स्थलाकृतिक मानचित्र के इतिहास का वर्णन कीजिए ?
Describe the history of topographic map
Answers
History of topographic map
Explanation:
On December 4–5, 1884, John Wesley Powell persuaded the U.S. Congress to authorize the U.S. Geological Survey (USGS) to begin systematic topographic mapping of the United States.
During the next 125 years, mapping techniques evolved from field surveys through photogrammetry to the computer-based methods currently used, and the scales and content of the topographic maps changed. It is the purpose of this two-part article to provide details of the USGS mapping processes through time and to help demonstrate that innovations by USGS employees and provision of public domain geospatial data helped spur the evolution and development of digital GIS and the commercial market for geospatial data and products of today. This first article describes topographic mapping developments prior to widespread use of GIS.
In the late 19th century, surveyors created topographic maps in the field. They measured a series of points in the field, using tape and compass traverses with elevations determined with an aneroid barometer and used in a process known as field sketching to draw a terrain representation using contours.