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34-618: Altamont Pass , formerly Livermore Pass , is a low mountain pass in the Diablo Range of Northern California between Livermore in the Livermore Valley and Tracy in the San Joaquin Valley . The name is actually applied to two distinct but nearby crossings of the range. The lower of the two, at an elevation of 741 ft (226 m), carries two railroad rights-of-way (ROWs) and Altamont Pass Road, part of

68-461: A stereoplotter . Modern mapping also employs lidar and other Remote sensing techniques. Older topographic maps were prepared using traditional surveying instruments. The cartographic style (content and appearance) of topographic maps is highly variable between national mapping organizations. Aesthetic traditions and conventions persist in topographic map symbology, particularly amongst European countries at medium map scales. Although virtually

102-415: A variety of methods . Traditional definitions require a topographic map to show both natural and artificial features. A topographic survey is typically based upon a systematic observation and published as a map series , made up of two or more map sheets that combine to form the whole map. A topographic map series uses a common specification that includes the range of cartographic symbols employed, as well as

136-531: A nearby mountainside, as with the Eisenhower Tunnel bypassing Loveland Pass in the Rockies, to allow faster traffic flow throughout the year. The top of a pass is frequently the only flat ground in the area, and may be a high vantage point. In some cases this makes it a preferred site for buildings. If a national border follows the ridge of a mountain range, a pass over the mountains is typically on

170-816: A standard geodetic framework that defines the map projection , coordinate system , ellipsoid and geodetic datum . Official topographic maps also adopt a national grid referencing system. Natural Resources Canada provides this description of topographic maps: These maps depict in detail ground relief (landforms and terrain), drainage (lakes and rivers), forest cover , administrative areas, populated areas, transportation routes and facilities (including roads and railways), and other man-made features. Other authors define topographic maps by contrasting them with another type of map; they are distinguished from smaller-scale " chorographic maps" that cover large regions, " planimetric maps" that do not show elevations, and " thematic maps " that focus on specific topics. However, in

204-786: A style of street racing which may take place on these roads. There are thousands of named passes around the world, some of which are well-known, such as the Khyber Pass close to the present-day Afghanistan-Pakistan border on the ancient Silk Road , the Great St. Bernard Pass at 2,473 metres (8,114 ft) in the Alps , the Chang La at 5,360 metres (17,590 ft), the Khardung La at 5,359 metres (17,582 ft) in Ladakh , India and

238-446: A topographic map. This includes not only how to identify map features, but also how to interpret contour lines to infer landforms like cliffs, ridges, draws, etc. Training in map reading is often given in orienteering, scouting, and the military. The various features shown on the map are represented by conventional signs or symbols. For example, colors can be used to indicate a classification of roads. These signs are usually explained in

272-888: Is also used, particularly in Europe. In the highest mountain range in the world, the Himalayas, passes are denoted by the suffix "La" in Tibetan, Ladhakhi, and several other regional languages. Examples are the Taglang La at 5,328 m (17,480 ft) on the Leh-Manali highway , and the Sia La at 5,589 m (18,337 ft) in the Eastern Karakoram range. Scotland has the Gaelic term bealach (anglicised "balloch"), while Wales has

306-413: Is analogous to the mathematical concept of a saddle surface , with a saddle point marking the minimum high point between two valleys and the lowest point along a ridge. On a topographic map , passes can be identified by contour lines with an hourglass shape, which indicates a low spot between two higher points. In the high mountains, a difference of 2,000 meters (6,600 ft) between the summit and

340-771: Is the Brenner pass in the Alps . Some mountain passes above the tree line have problems with snow drift in the winter. This might be alleviated by building the road a few meters above the ground, which will make snow blow off the road. There are many words for pass in the English-speaking world. In the United States, pass is very common in the West , the word gap is common in the southern Appalachians , notch in parts of New England , and saddle in northern Idaho . The term col , derived from Old French,

374-657: The Carte géométrique de la France , was completed in 1789. The Great Trigonometric Survey of India, started by the East India Company in 1802, then taken over by the British Raj after 1857 was notable as a successful effort on a larger scale and for accurately determining heights of Himalayan peaks from viewpoints over one hundred miles distant. Topographic surveys were prepared by the military to assist in planning for battle and for defensive emplacements (thus

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408-594: The Palakkad Gap at 140 metres (460 ft) in Palakkad , Kerala , India . The roads at Mana Pass at 5,610 metres (18,410 ft) and Marsimik La at 5,582 metres (18,314 ft), on and near the China–India border respectively, appear to be world's two highest motorable passes. Khunjerab Pass between Pakistan and China at 4,693 metres (15,397 ft) is also a high-altitude motorable mountain pass. One of

442-688: The federal government of the United States ' TIGER initiative compiled interlinked databases of federal, state and local political borders and census enumeration areas , and of roadways, railroads, and water features with support for locating street addresses within street segments. TIGER was developed in the 1980s and used in the 1990 and subsequent decennial censuses . Digital elevation models ( DEM ) were also compiled, initially from topographic maps and stereographic interpretation of aerial photographs and then from satellite photography and radar data . Since all these were government projects funded with taxes and not classified for national security reasons,

476-679: The Altamont Pass area was home to the Altamont Speedway , which became famous as the site of the 1969 Altamont Free Concert , a large outdoor concert featuring The Rolling Stones and marred by violence. The pass is also known for the Altamont Pass Wind Farm , one of the largest concentrations of wind turbines in the world. From the time of the California Gold Rush , what is now Altamont Pass

510-585: The Interior migrated to the newly created United States Geological Survey in 1879, where it has remained since. 1913 saw the beginning of the International Map of the World initiative, which set out to map all of Earth's significant land areas at a scale of 1:1 million, on about one thousand sheets, each covering four degrees latitude by six or more degrees longitude. Excluding borders, each sheet

544-506: The Stockton Road), was an early stagecoach route and formed part of the transcontinental Lincoln Highway . In 1938, Highway 50 , a four lane freeway (now called Interstate 580) was built through Altamont Pass, replacing the two-lane Altamont Pass Road and bypassing Altamont. Four westbound lanes were later constructed in 1970. Mountain pass Mountain passes make use of a gap , saddle , col or notch . A topographic saddle

578-458: The border, and there may be a border control or customs station, and possibly a military post. For instance, Argentina and Chile share the world's third-longest international border , 5,300 kilometres (3,300 mi) long, which runs north–south along the Andes mountains and includes 42 mountain passes. On a road over a pass, it is customary to have a small roadside sign giving the name of

612-528: The datasets were in the public domain and freely usable without fees or licensing. TIGER and DEM datasets greatly facilitated geographic information systems and made the Global Positioning System much more useful by providing context around locations given by the technology as coordinates. Initial applications were mostly professionalized forms such as innovative surveying instruments and agency-level GIS systems tended by experts. By

646-528: 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 and much less in others. Several commercial vendors supply international topographic map series. According to 2007/2/EC European directive , national mapping agencies of European Union countries must have publicly available services for searching, viewing and downloading their official map series. Topographic maps produced by some of them are available under

680-508: The famous but non-motorable mountain passes is Thorong La at 5,416 metres (17,769 ft) in Annapurna Conservation Area , Nepal. Topographic map In modern mapping, a topographic map or topographic sheet is a type of map characterized by large- scale detail and quantitative representation of relief features, usually using contour lines (connecting points of equal elevation), but historically using

714-440: The first artifacts to record observations about topography. Topographic maps are based on topographical surveys. Performed at large scales, these surveys are called topographical in the old sense of topography , showing a variety of elevations and landforms. This is in contrast to older cadastral surveys , which primarily show property and governmental boundaries. The first multi-sheet topographic map series of an entire country,

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748-459: The margin of the map, or on a separately published characteristic sheet. 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 . Contour lines are curves that connect contiguous points of

782-659: The mid-1990s, increasingly user-friendly resources such as online mapping in two and three dimensions, integration of GPS with mobile phones and automotive navigation systems appeared. As of 2011, the future of standardized, centrally printed topographical maps is left somewhat in doubt. Topographic maps have many multiple uses in the present day: any type of geographic planning or large-scale architecture ; Earth sciences and many other geographic disciplines; mining and other Earth-based endeavours; civil engineering and recreational uses such as hiking and orienteering . It takes practice and skill to read and interpret

816-434: The mountain is defined as a mountain pass. Passes are often found just above the source of a river , constituting a drainage divide . A pass may be very short, consisting of steep slopes to the top of the pass, or a valley many kilometers long, whose highest point might only be identifiable by surveying . Roads and railways have long been built through passes. Some high and rugged passes may have tunnels bored underneath

850-581: The name and history of the United Kingdom 's Ordnance Survey ). As such, elevation information was of vital importance. As they evolved, topographic map series became a national resource in modern nations in planning infrastructure and resource exploitation. In the United States, the national map-making function which had been shared by both the Army Corps of Engineers and the Department of

884-411: The old Lincoln Highway and the original alignment of US 50 before it was bypassed in 1937. The bypass route travels over the higher summit, at 1,009 ft (308 m), and now carries Interstate 580 , a major regional highway heavily congested by Central Valley suburbanization . Of the two railroad lines through the old pass, one is still in use: the ex- Western Pacific line built in 1908 over

918-573: The original Western Pacific Railroad (1862–1870) as part of the transcontinental railroad . After 1879, when a sea level ferry crossing at the Carquinez Strait replaced the 1869 route, it remained in use for other purposes by the Southern Pacific . In 1984 it was abandoned and deeded to Alameda County by Southern Pacific Railroad in favor of trackage rights on the aforementioned ex-Western Pacific line. From 1966 to 2008,

952-479: The pass and its elevation above mean sea level . Apart from offering relatively easy travel between valleys, passes also provide a route between two mountain tops with a minimum of descent. As a result, it is common for tracks to meet at a pass; this often makes them convenient routes even when travelling between a summit and the valley floor. Passes traditionally were places for trade routes, communications, cultural exchange, military expeditions etc. A typical example

986-545: The pass, which is sometimes known as the Altamont Corridor , now owned by Union Pacific . It carries freight trains as well as the Altamont Corridor Express , which gives its occasional name (ACE) and operates between Stockton , Livermore , Pleasanton , Fremont , and San Jose . The other and older right-of-way was the line built in 1869 with a 1,200-foot-long (370 m) summit tunnel by

1020-530: The same altitude ( isohypse ). In other words, every point on the marked line of 100 m elevation is 100 m above mean sea level. These maps usually 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 other features and points of interest such as what direction those streams are flowing. Most topographic maps were prepared using photogrammetric interpretation of aerial photography using

1054-696: The similar bwlch (both being insular Celtic languages). In the Lake District of north-west England, the term hause is often used, although the term pass is also common—one distinction is that a pass can refer to a route, as well as the highest part thereof, while a hause is simply that highest part, often flattened somewhat into a high-level plateau. In Japan they are known as tōge , which means "pass" in Japanese. The word can also refer to narrow, winding roads that can be found in and around mountains and geographically similar areas, or specifically to

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1088-407: The vernacular and day to day world, the representation of relief (contours) is popularly held to define the genre, such that even small-scale maps showing relief are commonly (and erroneously, in the technical sense) called "topographic". The study or discipline of topography is a much broader field of study, which takes into account all natural and human-made features of terrain. Maps were among

1122-428: Was 44 cm high and (depending on latitude) up to 66 cm wide. Although the project eventually foundered, it left an indexing system that remains in use. By the 1980s, centralized printing of standardized topographic maps began to be superseded by databases of coordinates that could be used on computers by moderately skilled end users to view or print maps with arbitrary contents, coverage and scale. For example,

1156-550: Was called Livermore's Pass after Robert Livermore , the owner of the Rancho Las Positas and a way station near the pass. After the transcontinental railroad was built through the pass by Chinese laborers in 1869, Altamont , formerly The Summit, became a critical stopping point where helper engines pushed heavy trains over the steep grades of the pass. A narrow road, the Altamont Pass Road (once called

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