Maps support the Coastal Zone Management and Energy Impact Programs and the offshore oil and gas program. Topo/Bathy Maps: Detailed multipurpose maps of NOS bathymetry and US Geological Survey (USGS) land topography. (Underwater Topography Maps) Geological survey The map serves as a tool for performing scientific, engineering, marine geophysical and environmental studies, that are required in the development of energy and marine resources. Detailed depth contours provide the size, shape, and distribution of underwater features. Types of Underwater Topography Maps: Underwater contours On one type of large-scale topographic map, called provisional, some symbols and lettering are hand-drawn.
Consequently, within the same series, maps may have slightly different symbols for the same feature.Įxamples of symbols that have changed include built-up areas, roads, intermittent drainage, and some lettering styles. These symbols are constantly refined to better relate to the features they represent, improve the appearance or readability of the map, or reduce production cost. The map includes symbols that represent such features as streets, buildings, streams, and vegetation. Contours make it possible to measure the height of mountains, depths of the ocean bottom, and steepness of slopes.Ī topographic map shows more than contours. Contours are imaginary lines that join points of equal elevation on the surface of the land above or below a reference surface, such as mean sea level. The distinctive characteristic of a topographic map is that the shape of the Earth’s surface is shown by contour lines.
A map is a representation of the Earth or part of it.
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