Topography is the study of the forms and features of land surfaces . The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps.
60-607: Gary Christopher Fisher (born November 5, 1950) is considered one of the inventors of the modern mountain bike . Fisher started competing in road and track races at age 12. He was suspended in 1968 because race organizers cited a rule that his hair was too long. By 1972 this rule had been repealed and Fisher's career continued. He won the TransAlp race in Europe and a Masters XC national title. Fisher went to work in 1974 on his 1930s Schwinn Excelsior X Bicycle. His innovations to
120-419: A 10-speed, 11-speed or 12-speed cassette, and the intricacies of a 10-speed, 11-speed or 12-speed rear derailleur were originally not found to be suitable combined with front shifters, although 10, 11 and 12 speed cassettes are now commonplace in single front chainring bicycles, and are also found on some mountain bikes. However, many pro-level mountain bikers have taken to using a narrower 10-speed road chain with
180-411: A 9-speed setup in an effort to reduce the weight of their bike. In early 2009, component group SRAM announced their release of their XX groupset, which uses a 2-speed front derailleur, and a 10-speed rear derailleur and cassette, similar to that of a road bike. Mud-shedding capabilities of their 10-speed XX cassette are made suitable for MTB use by extensive Computer Numerical Control (CNC) machining of
240-481: A Schwinn Varsity frame. Mert Lawwill had Terry Knight of Oakland build the frames. The bikes sold for about $ 500 new and were made from 1979 though 1980 (approximate run of 600 bikes). The first mass production mountain bike was the Specialized Stumpjumper , first produced in 1981. With the rising popularity of mountain bikes, Randolph (Randy) Ross, executive vice president of Ross Bicycles Inc. ,
300-454: A bicycle frame builder, used this idea and developed what is considered the first mountain bike. It was not until the late 1970s and early 1980s that road bicycle companies started to manufacture mountain bicycles using high-tech lightweight materials, such as M4 aluminum. The first production mountain bike available was the 1979 Lawwill Pro Cruiser. The frame design was based on a frame that Don Koski fabricated from electrical conduit and
360-413: A broader sense is used, particularly in medical fields such as neurology . An objective of topography is to determine the position of any feature or more generally any point in terms of both a horizontal coordinate system such as latitude, longitude, and altitude . Identifying (naming) features, and recognizing typical landform patterns are also part of the field. A topographic study may be made for
420-614: A frame with a suspension mechanism for the rear wheel. Rear suspension is ubiquitous in heavier-duty bikes and now common even in lighter bikes. Dropper seat posts can be installed to allow the rider to quickly adjust the seat height (an elevated seat position is more effective for pedaling, but poses a hazard in aggressive maneuvers). Mountain bikes are generally specialized for use on mountain trails, single track , fire roads , and other unpaved surfaces. In addition to being used to travel and recreate on those surfaces, many people use mountain bikes primarily on paved surfaces; some may prefer
480-589: A narrow sense involves the recording of relief or terrain , the three-dimensional quality of the surface, and the identification of specific landforms ; this is also known as geomorphometry . In modern usage, this involves generation of elevation data in digital form ( DEM ). It is often considered to include the graphic representation of the landform on a map by a variety of cartographic relief depiction techniques, including contour lines , hypsometric tints , and relief shading . The term topography originated in ancient Greece and continued in ancient Rome , as
540-486: A remote sensing technique that uses a laser instead of radio waves, has increasingly been employed for complex mapping needs such as charting canopies and monitoring glaciers. Terrain is commonly modelled either using vector ( triangulated irregular network or TIN) or gridded ( raster image ) mathematical models. In the most applications in environmental sciences , land surface is represented and modelled using gridded models. In civil engineering and entertainment businesses,
600-418: A seat tube angle around 73 degrees, with a head tube angle of anywhere from 60 to 73 degrees. The intended application of the bike affects its geometry very heavily. In general, steeper angles (closer to 90 degrees from the horizontal) are more efficient for pedaling up hills and make for sharper handling. Slacker angles (leaning farther from the vertical) are preferred for high speeds and downhill stability. In
660-420: A surface or extract land surface objects. The contour data or any other sampled elevation datasets are not a DLSM. A DLSM implies that elevation is available continuously at each location in the study area, i.e. that the map represents a complete surface. Digital Land Surface Models should not be confused with Digital Surface Models, which can be surfaces of the canopy, buildings and similar objects. For example, in
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#1732790135823720-405: A variety of reasons: military planning and geological exploration have been primary motivators to start survey programs, but detailed information about terrain and surface features is essential for the planning and construction of any major civil engineering , public works , or reclamation projects. There are a variety of approaches to studying topography. Which method(s) to use depends on
780-579: Is a bicycle designed for off-road cycling. Mountain bikes share some similarities with other bicycles, but incorporate features designed to enhance durability and performance in rough terrain, which often makes them heavier, more complex and less efficient on smooth surfaces. These typically include a suspension fork , large knobby tires , more durable wheels , more powerful brakes, straight, wide handlebars to improve balance and comfort over rough terrain, and wide-ratio gearing optimized for topography , application (e.g., steep climbing or fast descending) and
840-582: Is a field of geoscience and planetary science and is concerned with local detail in general, including not only relief , but also natural , artificial, and cultural features such as roads, land boundaries, and buildings. In the United States, topography often means specifically relief , even though the USGS topographic maps record not just elevation contours, but also roads, populated places, structures, land boundaries, and so on. Topography in
900-413: Is a general term for geodata collection at a distance from the subject area. Besides their role in photogrammetry, aerial and satellite imagery can be used to identify and delineate terrain features and more general land-cover features. Certainly they have become more and more a part of geovisualization , whether maps or GIS systems. False-color and non-visible spectra imaging can also help determine
960-460: Is concerned with underlying structures and processes to the surface, rather than with identifiable surface features. The digital elevation model (DEM) is a raster -based digital dataset of the topography ( hypsometry and/or bathymetry ) of all or part of the Earth (or a telluric planet ). The pixels of the dataset are each assigned an elevation value, and a header portion of the dataset defines
1020-437: Is especially noticeable when cycling on roads and hard trails. At first, early rear suspension designs were overly heavy, and susceptible either to pedaling-induced bobbing or lockout. Most new mountain bikes use disc brakes. They offer much improved stopping power (less lever pressure is required providing greater braking modulation) over rim brakes under all conditions especially adverse conditions, because they are located at
1080-525: Is raw and uninterpreted. It may contain holes (due to cloud cover for example) or inconsistencies (due to the timing of specific image captures). Most modern topographic mapping includes a large component of remotely sensed data in its compilation process. In its contemporary definition, topographic mapping shows relief. 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
1140-422: Is to something else). Topography has been applied to different science fields. In neuroscience , the neuroimaging discipline uses techniques such as EEG topography for brain mapping . In ophthalmology , corneal topography is used as a technique for mapping the surface curvature of the cornea . In tissue engineering , atomic force microscopy is used to map nanotopography . In human anatomy , topography
1200-674: Is used in the ETRTO tire and rim sizing system), and the average 29″ mountain bike tire is (in ISO notation) 59-622 corresponds to an outside diameter of about 29.15 inches (740 mm). 622 mm wheels are standard on road bikes and are commonly known as 700C. In some countries, mainly in Continental Europe , 700C (622 mm) wheels are commonly called 28 inch wheels. 24 inch wheels are used for dirt jumping bikes and sometimes on freeride bikes, rear wheel only, as this makes
1260-559: The FMB World Tour and the Red Bull Rampage . Mountain bikes can usually be divided into four broad categories based on suspension configuration: Since the 1980s, mountain bikes have had anywhere from 7 to 36 speeds, with 1 to 4 chain-rings on the crankset and 5 to 12 sprockets in the cogset . 30-speed, 33-speed and 36-speed mountain bikes were originally found to be unworkable, as the mud-shedding capabilities of
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#17327901358231320-651: The "Topographical Bureau of the Army", formed during the War of 1812 , which became the Corps of Topographical Engineers in 1838. After the work of national mapping was assumed by the U.S. Geological Survey in 1878, the term topographical remained as a general term for detailed surveys and mapping programs, and has been adopted by most other nations as standard. In the 20th century, the term topography started to be used to describe surface description in other fields where mapping in
1380-411: The 1.90 to 2.10 in (48 to 53 mm ) size, to 2.35 and 3.00 in (60 and 76 mm) widths popular with freeride and downhill bicycles. Although heavier wheelsets are favored in the freeride and downhill disciplines, advances in wheel technology continually shave weight off strong wheels. This is highly advantageous as rolling weight greatly affects handling and control, which are very important to
1440-413: The 27.5-inch wheel diameter with ≈2.25 widths (ISO 584 mm rim diameter), particular on smaller frame sizes for shorter riders. Mountain bikes with 24-inch wheels are also available, sometimes for dirt jumping, or as a junior bike. Bicycle wheel sizes are not precise measurements: a 29-inch mountain bike wheel with a 622 millimetres (24.5 in) bead seat diameter (the term, bead seat diameter (BSD),
1500-604: The Continental U.S., for example), the compiled data forms the basis of basic digital elevation datasets such as USGS DEM data. This data must often be "cleaned" to eliminate discrepancies between surveys, but it still forms a valuable set of information for large-scale analysis. The original American topographic surveys (or the British "Ordnance" surveys) involved not only recording of relief, but identification of landmark features and vegetative land cover. Remote sensing
1560-535: The acquisition of Fisher by Trek Bicycle Corporation . On June 16, 2010, Trek Bicycle Corporation announced "the Gary Fisher Collection, a line of Trek bikes that will replace the standalone Gary Fisher brand". Fisher remains involved with design and marketing, along with being scout and mentor to racers sponsored by the team. The best known was the gold-medal winner in the 1996 and 2000 Olympics women's mountain biking: Paola Pezzo . Fisher
1620-748: The acronym "ATB" are used as synonyms for "mountain bike", but some authors consider them passé. The original mountain bikes were modified heavy cruiser bicycles used for freewheeling down mountain trails. The sport became popular in the 1970s in Northern California, USA, with riders using older, single-speed balloon tire bicycles to ride down rugged hillsides. These modified bikes were called "ballooners" in California, "klunkers" in Colorado, and "dirt bombers" in Oregon. Joe Breeze ,
1680-669: The area of coverage, the units each pixel covers, and the units of elevation (and the zero-point). DEMs may be derived from existing paper maps and survey data, or they may be generated from new satellite or other remotely sensed radar or sonar data. A geographic information system (GIS) can recognize and analyze the spatial relationships that exist within digitally stored spatial data. These topological relationships allow complex spatial modelling and analysis to be performed. Topological relationships between geometric entities traditionally include adjacency (what adjoins what), containment (what encloses what), and proximity (how close something
1740-455: The basis for much derived topographic work. Digital Elevation Models, for example, have often been created not from new remote sensing data but from existing paper topographic maps. Many government and private publishers use the artwork (especially the contour lines) from existing topographic map sheets as the basis for their own specialized or updated topographic maps. Topographic mapping should not be confused with geologic mapping . The latter
1800-441: The bike more maneuverable. 29 inch wheels were once used for only cross country purposes, but are now becoming more commonplace in other disciplines of mountain biking. A mountain bike with 29″ wheels is often referred to as a 29er , and a bike with 27.5-inch wheels is called a 27.5 Mountain bike or as a marketing term ″650B bike". Wheels come in a variety of widths, ranging from standard rims suitable for use with tires in
1860-747: The case of surface models produces using the lidar technology, one can have several surfaces – starting from the top of the canopy to the actual solid earth. The difference between the two surface models can then be used to derive volumetric measures (height of trees etc.). Topographic survey information is historically based upon the notes of surveyors. They may derive naming and cultural information from other local sources (for example, boundary delineation may be derived from local cadastral mapping). While of historical interest, these field notes inherently include errors and contradictions that later stages in map production resolve. As with field notes, remote sensing data (aerial and satellite photography, for example),
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1920-499: The cassette. Due to the time and cost involved in such a product, they were only aimed at top-end XC-racers. However, 10-speed has become the norm by 2011 and the market leader Shimano even offers its budget groupset "Alivio" in a 10-speed version. In July 2012, SRAM announced a 1×11 drivetrain called XX1 that does not make use of a front derailleur for lighter weight and simplicity. In the 2014 Commonwealth Games at Glasgow all leading riders used 1×11 drivetrains. SRAM's new 1×12 gearing
1980-443: The center of the wheel (on the wheel hub). They therefore remain drier and cleaner than wheel rims, which are more readily soiled or damaged. The disadvantage of disc brakes is their increased cost and often greater weight. Disc brakes do not allow heat to build up in the tires on long descents; instead, heat builds up in the rotor, which can become extremely hot. There are two different kinds of disc brakes: hydraulic, which uses oil in
2040-414: The common points are identified on each image . A line of sight (or ray ) can be built from the camera location to the point on the object. It is the intersection of its rays ( triangulation ) which determines the relative three-dimensional position of the point. Known control points can be used to give these relative positions absolute values. More sophisticated algorithms can exploit other information on
2100-454: 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. While not officially "topographic" maps, the national surveys of other nations share many of the same features, and so they are often called "topographic maps." Existing topographic survey maps, because of their comprehensive and encyclopedic coverage, form
2160-520: The detailed description of a place. The word comes from the Greek τόπος ( topos , "place") and -γραφία ( -graphia , "writing"). In classical literature this refers to writing about a place or places, what is now largely called ' local history '. In Britain and in Europe in general, the word topography is still sometimes used in its original sense. Detailed military surveys in Britain (beginning in
2220-566: The development of the sport of mountain biking in the 1970s, many new subtypes of mountain biking have developed, such as cross-country (XC) , trail , all-mountain , enduro , freeride , downhill , and a variety of track and slalom types. Each of these place different demands on the bike, requiring different designs for optimal performance. MTB development has led to an increase in suspension travel, now often up to 8 inches (200 mm), and gearing up to 13 speed, to facilitate both climbing and rapid descents. Advances in gearing have also led to
2280-507: The first company to specialize in the manufacture of this type of bicycle. Frames were built by Tom Ritchey , who later founded his own company. The first model sold for $ 1,300; 160 were manufactured in the first year. 1979 saw the introduction of Shimano components and an ill-fated attempt to trademark Mountain Bike . The company dissolved in 1983; Fisher founded Gary Fisher Mountain Bikes
2340-538: The first topographic maps was begun in France by Giovanni Domenico Cassini , the great Italian astronomer. Even though remote sensing has greatly sped up the process of gathering information, and has allowed greater accuracy control over long distances, the direct survey still provides the basic control points and framework for all topographic work, whether manual or GIS -based. In areas where there has been an extensive direct survey and mapping program (most of Europe and
2400-495: The front and rear wheel are fitted with a shock absorber in some form as the wheel attaches to the bike. This provides a smoother ride as the front and rear wheels can now travel up and down to absorb the force of obstacles striking the tires. Dual suspension bikes of a similar quality are considerably more expensive, but this price increase brings an enormous off-road performance upgrade as dual suspension bikes are much faster on downhill and technical/rough sections, than other forms of
2460-403: The hardtail design has the benefits of lower cost, less maintenance, and better pedaling efficiency, it is slowly losing popularity due to improvements in full suspension designs. Front fork suspensions are now available with 8 inches (200 mm) of travel or more (see above under Designs .) Many new mountain bikes integrate a "full suspension" design known as dual suspension, meaning that both
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2520-459: The late eighteenth century) were called Ordnance Surveys , and this term was used into the 20th century as generic for topographic surveys and maps. The earliest scientific surveys in France were the Cassini maps after the family who produced them over four generations. The term "topographic surveys" appears to be American in origin. The earliest detailed surveys in the United States were made by
2580-456: The lie of the land by delineating vegetation and other land-use information more clearly. Images can be in visible colours and in other spectrum. Photogrammetry is a measurement technique for which the co-ordinates of the points in 3D of an object are determined by the measurements made in two photographic images (or more) taken starting from different positions, usually from different passes of an aerial photography flight. In this technique,
2640-440: The lines to push the brake pads against the rotors to stop the bike. They cost more but work better. Mechanical, which uses wires in the lines to pull the pads against the rotors. Typical features of a mountain bike are very wide tyres. The original 26 inch wheel diameter with ≈2.125″ width ( ISO 559 mm rim diameter) is increasingly being displaced by 29-inch wheels with ≈2.35″ width (ISO 622 mm rim diameter), as well as
2700-488: The model included drum brakes, motorcycle brake levers and cables, and triple chain–rings, all taken from "junkers" Fisher found at bike shops. The next year, Fisher participated in the Repack downhill race, promoted by his roommate Charlie Kelly . This used a tortuous downhill route on Pine Mountain near Fairfax, California , just north of San Francisco, in which riders used their coaster brakes so much that they had to repack
2760-479: The most representations of land surface employ some variant of TIN models. In geostatistics , land surface is commonly modelled as a combination of the two signals – the smooth (spatially correlated) and the rough (noise) signal. In practice, surveyors first sample heights in an area, then use these to produce a Digital Land Surface Model in the form of a TIN . The DLSM can then be used to visualize terrain, drape remote sensing images, quantify ecological properties of
2820-535: The mountain bike. This is because when the wheel strikes an obstacle its tendency is to bounce up. Due to some forward energy being lost in the upward movement some speed is lost. Dual suspension bikes solve this problem by absorbing this upward force and transmit it into the shocks of the front and rear wheels, drastically decreasing the translation of forward momentum into useless upward movement. Disadvantages of rear suspension are increased weight, increased price, and with some designs, decreased pedaling efficiency, which
2880-478: The past mountain bikes had a rigid frame and fork. In the early 1990s, the first mountain bikes with suspension forks were introduced. This made riding on rough terrain easier and less physically stressful. The first front suspension forks had about 1 1 ⁄ 2 to 2 inches (38 to 50 mm) of suspension travel. Once suspension was introduced, bikes with front suspension and rigid, non-suspended rear wheels, or "hardtails", became popular nearly overnight. While
2940-533: The same intended application, more expensive tires tend to be lighter and have less rolling resistance. Sticky rubber tires are now available for use on freeride and downhill bikes. While these tires wear down more quickly, they provide greater traction in all conditions, especially during cornering. Tires and rims are available in either tubed or tubeless designs, with tubeless tires recently (2004) gaining favor for their pinch flat resistance. Tires also come with tubes, tubeless and tubeless-ready. Tires with tubes are
3000-703: The same year. Fisher sold his company in 1991 to Taiwan's Anlen company, staying on as President. Fisher developed the first commercially produced full suspension bicycles designed by Mert Lawwill , a former champion motorcycle racer. His bike, the Gary Fisher RS-1, was released in 1992. Its rear suspension adapted the A-arm suspension design from sports car racing, and was the first four-bar linkage in mountain biking. In 1992, Howie Cohen, who had previously imported Nishiki , Azuki and Kuwahara bicycles, assisted Gary Fisher with his brand, 18 months later brokering
3060-425: The scale and size of the area under study, its accessibility, and the quality of existing surveys. Surveying helps determine accurately the terrestrial or three-dimensional space position of points and the distances and angles between them using leveling instruments such as theodolites , dumpy levels and clinometers . GPS and other global navigation satellite systems (GNSS) are also used. Work on one of
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#17327901358233120-462: The scene known a priori (for example, symmetries in certain cases allowing the rebuilding of three-dimensional co-ordinates starting from one only position of the camera). Satellite RADAR mapping is one of the major techniques of generating Digital Elevation Models (see below). Similar techniques are applied in bathymetric surveys using sonar to determine the terrain of the ocean floor. In recent years, LIDAR ( LI ght D etection A nd R anging),
3180-463: The smoking hubs with grease after every run. Fisher holds the record time on the Repack course at 4:22. Gary Fisher speaks about his role as a pioneer in the sport of mountain biking in two video documentaries: Full Cycle: A World Odyssey (1994) and Klunkerz (2007). Original clips of Fisher on his mountain bike appear in both documentaries. Gary Fisher coined the term mountain bike in 1979. That year, Fisher and Kelly founded MountainBikes,
3240-878: The standard design and the easiest to use and maintain. Tubeless tires are significantly lighter and often have better performance because you can run them at a lower tire pressure which results in better traction and increasing rolling resistance. Tubeless-ready tires are tires that can use tubes or go tubeless. A liquid sealant is used without the tube to secure the seal to the rim. Popular tire manufacturers include Wilderness Trail Bikes , Schwalbe, Maxxis, Nokian, Michelin, Continental, Tioga, Kenda, Hutchinson, Specialized and Panaracer. Mountain bikes are available in tandem configurations. For example, Cannondale and Santana Cycles offer ones without suspension, while Ellsworth , Nicolai, and Ventana manufacture tandems with full suspension. [REDACTED] Media related to Mountain bikes at Wikimedia Commons Topography Topography
3300-686: The technical nature of freeride and downhill riding. The widest wheel/tire widths, typically 3.8 in (97 mm) or larger, are sometimes used by icebikers who use their mountain bikes for winter-time riding in snowy conditions. Manufacturers produce bicycle tires with a wide variety of tread patterns to suit different needs. Among these styles are: slick street tires, street tires with a center ridge and outer tread, fully knobby, front-specific, rear-specific, and snow studded. Some tires can be specifically designed for use in certain weather (wet or dry) and terrain (hard, soft, muddy, etc.) conditions. Other tire designs attempt to be all-around applicable. Within
3360-443: The ubiquity of "1x" drivetrains (pronounced "one-by"), simplifying the gearing to one chainring in the front and a wide range cassette at the rear, typically with 9 to 12 sprockets . 1x gearing reduces overall bike weight, increases ground clearance, and greatly simplifies the process of gear selection, but 2- or 3-ring drivetrains are still common on entry-level bikes. The expressions "all terrain bicycle", "all terrain bike", and
3420-593: The upright position, plush ride, and stability that mountain bikes often have. Mountain biking terrain commonly has rocks, roots, loose dirt, and steep grades. Many trails have additional technical trail features (TTF) such as log piles , log rides , rock gardens , skinnies , gap jumps , and wall-rides . Mountain bikes are built to handle these types of terrain and features. The heavy-duty construction combined with stronger rims and wider tires has also made this style of bicycle popular with urban riders and couriers who must navigate through potholes and over curbs. Since
3480-467: Was inducted into the Mountain Bike Hall of Fame in 1988. Outside magazine named him one of the "50 who left their mark" in the sport in 2000, and Smithsonian magazine honored him in 1994 as the "Founding Father of Mountain Bikes." In 1998, Fisher was recognized by Popular Mechanics for his innovations in sports. Mountain bike A mountain bike ( MTB ) or mountain bicycle
3540-430: Was introduced in 2016 as SRAM Eagle. This gives a single chain ring bike better ability to climb. The critical angles in bicycle geometry are the head angle (the angle of the head tube ), and the seat tube angle (the angle of the seat tube ). These angles are measured from the horizontal, and drastically affect the rider position and performance characteristics of the bicycle. Mountain bike geometry will often feature
3600-507: Was quoted in the New York Times saying I'd say these bikes are one of the biggest things that ever happened to the biking industry. Its basic look constitutes "a total shift in image" for the industry. Throughout the 1990s and 2000s, mountain biking moved from a little-known sport to a mainstream activity complete with an international racing circuit and a world championship , in addition to various free ride competitions, such as
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