When.com Web Search

Search results

1. Results From The WOW.Com Content Network

2. Contour line - Wikipedia

   en.wikipedia.org/wiki/Contour_line

   A contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes. [4] The contour interval of a contour map is the difference in elevation between successive contour lines. [5] The gradient of the function is always perpendicular to the contour ...

3. Topographic map - Wikipedia

   en.wikipedia.org/wiki/Topographic_map

   Topographic maps are also commonly called contour maps or topo maps. In the United States, where the primary national series is organized by a strict 7.5-minute grid, they are often called or quads or quadrangles. Topographic maps conventionally show topography, or land contours, by means of contour lines.

4. Geographic information system - Wikipedia

   en.wikipedia.org/wiki/Geographic_Information_System

   A GIS, however, can be used to depict two- and three-dimensional characteristics of the Earth's surface, subsurface, and atmosphere from information points. For example, a GIS can quickly generate a map with isopleth or contour lines that indicate differing amounts of rainfall. Such a map can be thought of as a rainfall contour map.

5. Triangulated irregular network - Wikipedia

   en.wikipedia.org/wiki/Triangulated_irregular_network

   The TIN model was developed in the early 1970s as a simple way to build a surface from a set of irregularly spaced points. The first triangulated irregular network program for GIS was written by W. Randolph Franklin, under the direction of David Douglas and Thomas Peucker (Poiker), at Canada's Simon Fraser University, in 1973. [2]

6. Topography - Wikipedia

   en.wikipedia.org/wiki/Topography

   In the United States, USGS topographic maps show relief using contour lines. The USGS calls maps based on topographic surveys, but without contours, "planimetric maps." These maps show not only the contours, but also any significant streams or other bodies of water, forest cover, built-up areas or individual buildings (depending on scale), and ...

7. List of GIS data sources - Wikipedia

   en.wikipedia.org/wiki/List_of_GIS_data_sources

   Online collection of all digital USGS 1:24K scale topographic maps (as well as various other GIS data) covering the United States, available as a free download. NPScape United States Department of the Interior National Park Service NPScape is a landscape dynamics monitoring project that provides landscape-level data, tools, and evaluations for ...