Topographic map
A 1766 map of Hartfordshire by Andrew Dury and John Andrews displayed roads, lanes, churches, and the seats of noblemen using hachures to show relief. This early work stands in contrast to older cadastral surveys that primarily showed property and governmental boundaries. Modern definitions require a topographic map to show both natural and artificial features with large-scale detail. P.D.A. Harvey described such maps as setting out to convey the shape and pattern of landscape within one's own direct experience. They differ from smaller-scale chorographic maps that cover whole provinces or continents. A planimetric map does not show elevations, whereas a topographic map presents horizontal and vertical positions in measurable form. The main division of traditional maps remains between those supplying a general image of the earth's surface and thematic maps focusing on specific topics.
The first multi-sheet topographic map series of an entire country was completed in France in 1789 under the name Carte géométrique de la France. The Great Trigonometric Survey of India began in 1802 under the East India Company and later came under British Raj control after 1857. This massive project accurately determined heights of Himalayan peaks from viewpoints over one hundred miles distant. Topographical surveys were originally performed at large scales to show a variety of elevations and landforms. These surveys became national resources for planning infrastructure and resource exploitation in modern nations. In the United States, the national map-making function migrated to the newly created United States Geological Survey in 1879. That agency has retained this responsibility ever since while sharing it previously with both the Army Corps of Engineers and the Department of the Interior.
Topographic surveys were prepared by the military to assist in planning for battle and for defensive emplacements. Elevation information proved vital for these defense purposes, leading to the history of the United Kingdom's Ordnance Survey. The range of information indicated by early maps included every thing remarkable in the county being surveyed. As they evolved, these map series became essential tools for infrastructure development and resource exploitation across different countries. The United States government funded datasets that were not classified for national security reasons. These public domain datasets allowed free use without fees or licensing for anyone who needed them. Digital elevation models were compiled initially from topographic maps and stereographic interpretation of aerial photographs before moving to satellite photography and radar data.
By the 1980s centralized printing of standardized topographic maps began to be superseded by databases of coordinates usable on computers. The federal government of the United States developed the TIGER initiative which compiled interlinked databases of political borders and census enumeration areas. This system also tracked roadways, railroads, and water features with support for locating street addresses within street segments. TIGER was developed during the 1980s and used in the 1990 decennial census and subsequent counts. Initial applications mostly took professionalized forms such as innovative surveying instruments and agency-level GIS systems tended by experts. By the mid-1990s increasingly user-friendly resources appeared including online mapping in two and three dimensions. Integration of GPS with mobile phones and automotive navigation systems emerged alongside these digital advancements. As of 2011 the future of standardized centrally printed topographical maps remained somewhat in doubt.
Topographic maps conventionally show land contours by means of contour lines that connect contiguous points of the same altitude. Every point on a marked line of 100 meters elevation sits exactly 100 meters above mean sea level. These maps usually show significant streams or other bodies of water along with forest cover and built-up areas. Individual buildings appear depending on scale while other features include what direction those streams are flowing. Most topographic maps were prepared using photogrammetric interpretation of aerial photography using a stereoplotter. Modern mapping now employs lidar and other remote sensing techniques to gather data. Older topographic maps were prepared using traditional surveying instruments before these new technologies existed. The cartographic style remains highly variable between national mapping organizations despite persistent aesthetic traditions.
According to 2007/2/EC European directive national mapping agencies of European Union countries must have publicly available services for searching their official map series. Topographic maps produced by some of them are available under a free license that allows re-use such as a Creative Commons license. Although virtually the entire terrestrial surface of Earth has been mapped at scale 1:1,000,000 medium and large-scale mapping has been accomplished intensively in some countries. Several commercial vendors supply international topographic map series to meet global demand. Aesthetic traditions and conventions persist in topographic map symbology particularly amongst European countries at medium map scales. The International Map of the World initiative set out to map all significant land areas at a scale of 1:1 million starting in 1913. That project eventually foundered but left an indexing system that remains in use today across many nations.
Continue Browsing
Common questions
What is a topographic map and how does it differ from other maps?
A topographic map shows both natural and artificial features with large-scale detail. It presents horizontal and vertical positions in measurable form unlike planimetric maps that do not show elevations.
When was the first multi-sheet topographic map series of an entire country completed?
The first multi-sheet topographic map series of an entire country was completed in France in 1789 under the name Carte géométrique de la France.
Who created the Great Trigonometric Survey of India and when did it begin?
The Great Trigonometric Survey of India began in 1802 under the East India Company and later came under British Raj control after 1857.
How are land contours shown on topographic maps?
Topographic maps conventionally show land contours by means of contour lines that connect contiguous points of the same altitude. Every point on a marked line of 100 meters elevation sits exactly 100 meters above mean sea level.
Which agency manages national map-making functions in the United States since 1879?
In the United States the national map-making function migrated to the newly created United States Geological Survey in 1879. That agency has retained this responsibility ever since while sharing it previously with both the Army Corps of Engineers and the Department of the Interior.