![]() ![]() The keyline of this primary valley is determined by pegging a contour line that conforms to the natural shape of the valley through the keypoint, such that all points on the keyline are at the same elevation as the keypoint. In a smooth, grassy valley, a location denominated the keypoint is identified at which the lower and leveller portion of the primary valley floor suddenly steepens higher. Rancho San Ricardo, Oaxaca, México Keypoint ![]() roads, fences, trees, and edifices, which if so located would help optimize the natural potential of the land in question. The identified natural water lines delineate the possible locations for the various less permanent elements, e. Constructing interconnecting channels may be part of such optimization. On undulating land, keyline design involves identifying ridges, valleys, and natural water courses and designing with them in mind in order to optimize water storage sites. Keyline design considers these elements in planning the placement of water storage features, roads, trees, edifices, and fences. The Scale identifies the environmental elements of typical farms and orders them according to their degree of permanence as follows: The foundation of Yeomans' Keyline design system is the Keyline Scale of Permanence (KSOP), which was the outcome of 15 years of adaptive experimentation on his properties Yobarnie and Nevallan. Roads follow both ridge lines and water channels to provide easier movement across the land. Graded earthen channels may be interlinked to broaden the catchment areas of high dams, conserve the height of water, and transfer rainfall runoff into the most efficient high dam sites. Keyline designs include irrigation dams equipped with through-the-wall lockpipe systems, gravity feed irrigation, stock water, and yard water. Yeomans described a system of amplified contour ripping to control rainfall runoff and enable fast flood irrigation of undulating land without the need for terracing it. Yeomans published the first book on Keyline design in 1954. Yeomans invented and developed Keyline design in his books The Keyline Plan, The Challenge of Landscape, Water For Every Farm, and The City Forest. Keyline design is a system of principles and techniques of developing rural and urban landscapes to optimize use of their water resources.Īustralian farmer and engineer P. The "keyline" is a specific topographic feature related to the natural flow of water on the tract. Keyline design is a landscaping technique of maximizing the beneficial use of the water resources of a tract of land. The USGS also publishes other kinds of maps, including some topographic maps that are not standard quadrangle maps.A keyline irrigation channel in Orana, Australia Exclusive to the topoBuilder application is the ability to center maps wherever users choose. These maps utilize the best available data from The National Map. OnDemand Topos enable users to request customized USGS-style topographic maps.The Historical Topographic Map Collection is scanned images of maps originally published (at all scales) as paper documents in the period 1884-2006. US Topo maps are the current topographic map series, published as digital documents (that can also be printed) from 2009 to the present. Within this domain there are three product categories: That covers a quadrangle that measures 7.5 minutes of longitude and latitude on all sides, so these are also referred to as 7.5-minute maps, quadrangle maps, or “quad” maps (modern topographic maps for Alaska have a scale of 1:25,000 and cover a variable distance of longitude). Each topographic map has a unique name. The phrase "USGS topographic map" can refer to maps with a wide range of scales, but the scale used for all modern USGS topographic maps is 1:24,000. Those will be added to more current maps over time. Older maps (published before 2006) show additional features such as trails, buildings, towns, mountain elevations, and survey control points. USGS topographic maps also show many other kinds of geographic features including roads, railroads, rivers, streams, lakes, boundaries, place or feature names, mountains, and much more. Contours make it possible to show the height and shape of mountains, the depths of the ocean bottom, and the steepness of slopes. Elevation contours are imaginary lines connecting points having the same elevation on the surface of the land above or below a reference surface, which is usually mean sea level. The distinctive characteristic of a topographic map is the use of elevation contour lines to show the shape of the Earth's surface. ![]()
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