query: what is a contour line on a topographic map

pos: Contour line Contour line A contour line (also isoline, isopleth, or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value. It is a plane section of the three-dimensional graph of the function "f"("x", "y") parallel to the "x", "y" plane. In cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. A contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys

pos: Contour line Contour line A contour line (also isoline, isopleth, or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value. It is a plane section of the three-dimensional graph of the function "f"("x", "y") parallel to the "x", "y" plane. In cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. A contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys

neg: Line of greatest slope possible path. The line of greatest slope has practical significance in map reading. On the terrain it is often far more discernible, even intuitively obvious, rather than accurately picking out the consistent height level on what is likely the undulating uneven ground along the ground represented on the contour line. But knowing that a greatest slope vector is orthogonal to the contour line, one can readily deduce the direction of the contour lines from the line of greatest slope. The extent and overall direction of the contour line to a map scale can only be found on the topographic map.

neg: Topographic map Topographic map In modern mapping, a topographic map is a type of map characterized by large-scale detail and quantitative representation of relief, usually using contour lines, but historically using a variety of methods. Traditional definitions require a topographic map to show both natural and man-made features. A topographic survey is typically published as a map series, made up of two or more map sheets that combine to form the whole map. A contour line is a line connecting places of equal elevation. Natural Resources Canada provides this description of topographic maps: Other authors define topographic maps by contrasting them with

neg: Topographic map protect natural resources and the public at large, or because such features are not present in any public domain database. Topographic map In modern mapping, a topographic map is a type of map characterized by large-scale detail and quantitative representation of relief, usually using contour lines, but historically using a variety of methods. Traditional definitions require a topographic map to show both natural and man-made features. A topographic survey is typically published as a map series, made up of two or more map sheets that combine to form the whole map. A contour line is a line connecting places of

neg: Contour line the reader to decipher the background information in the map itself. If there is little or no content on the base map, the contour lines may be drawn with relatively heavy thickness. Also, for many forms of contours such as topographic maps, it is common to vary the line weight and/or color, so that a different line characteristic occurs for certain numerical values. For example, in the topographic map above, the even hundred foot elevations are shown in a different weight from the twenty foot intervals. Line color is the choice of any number of pigments that suit the display.

neg: Topographic profile Topographic profile A topographic profile or topographic cut is a representation of the relief of the terrain that is obtained by cutting transversely the lines of a topographic map. Each contour line can be defined as a closed line joining relief points at equal height above sea level. It is usually drawn on the same horizontal scale as the map, but the use of an exaggerated vertical scale is advisable to underline the elements of the relief. This can vary according to the slope and amplitude of the terrestrial relief, but is usually three to five times the horizontal scale.

neg: Topographic map 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 "topo 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 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

neg: Map symbolization intervals of 10 feet or less. Areas that contain mountain or other high slope can use an interval of 100 feet. Apart from showing just contour lines, topographic maps also use a lot of map symbols to represent its features. Features are represented by using point, line, and area symbols. Individual features, such as houses, are shown as point symbols like a small dot or square. However, a cluster of houses or neighborhood can be shown as a shaded area or polygon. Areas of importance or landmarks may receive special symbols that represent what they are. For instance, a church

neg: Topographic prominence of the higher contour line nearest the saddle. This gives a lower bound on the possible prominence of the peak, ignoring map error; inaccuracies in mapping lead to further uncertainties and a larger error bound. "Optimistic" prominence assumes that the col is as low as possible, yielding an upper bound value for the prominence. "Midrange" or "mean" prominence uses the mean of these two values. "Mean" prominence is sometimes referred to as "rise". In Britain, where topographic mapping is more detailed than in many countries, it is customary to use a fourth method: "interpolated" prominence. The true prominence is estimated

neg: Lake Murray (South Carolina) industrial northeast. He also had been the chief engineer on the project to electrify the New Haven Railroad out of New York City. Once Williams came to Murray to make his proposal in 1923, Murray and his partner, Henry Flood, Jr., pored over topographic maps of the region and worked on estimates. It looked as if they might be able to generate enormous power at very low cost. It was said that here, as Murray looked over a topographic map of the Saluda River Valley, his eyes glanced at the contour line. He followed the line as it meandered through

neg: Stream gradient the hard layer. Human dams, glaciation, changes in sea level, and many other factors can also change the "normal" or "natural" gradient pattern. On topographic maps, stream gradient can be easily approximated if the scale of the map and the contour intervals are known. Contour lines form a V-shape on the map, pointing upstream. By counting the number of lines that cross a certain segment of a stream, multiplying this by the contour interval, and dividing that quantity by the length of the stream segment, one obtains an approximation to the stream gradient. Because stream gradient is customarily given in

neg: Cartography in order to design a map with a specific audience in mind. Oftentimes, the type of audience an orienteering map is made for is in a particular industry or occupation. An example of this kind of map would be a municipal utility map. A topographic map is primarily concerned with the topographic description of a place, including (especially in the 20th and 21st centuries) the use of contour lines showing elevation. Terrain or relief can be shown in a variety of ways (see Cartographic relief depiction). In the present era, one of the most widespread and advanced methods used to

neg: Cardinal direction are north, south, east, west, up and down. In this context, up and down relate to elevation, altitude, or possibly depth (if water is involved). The topographic map is a special case of cartography in which the elevation is indicated on the map, typically via contour lines. In astronomy, "cardinal points" of the disk of an astronomical body may be four points defined by the direction in which the celestial poles are located, as seen from the center of the disk. A line (here it is a great circle on the celestial sphere) drawn from the center of the disk

neg: Orienteering map Orienteering map An orienteering map is a map specially prepared for use in orienteering competitions. It is a topographic map with extra details to help the competitor navigate through the competition area. These maps are much more detailed than general-purpose topographic maps, and incorporate a standard symbology that is designed to be useful to anyone, regardless of native language. In addition to indicating the topography of the terrain with contour lines, orienteering maps also show forest density, water features, clearings, trails and roads, earthen banks and rock walls, ditches, wells and pits, fences and power lines, buildings, boulders, and other

neg: Topographic prominence Topographic prominence In topography, prominence measures the height of a mountain or hill's summit relative to the lowest contour line encircling it but containing no higher summit within it. It is a measure of the independence of a summit. A peak's "key col" (highest gap between two mountains) is a unique point on this contour line and the parent peak is some higher mountain, selected according to various objective criteria. There are at least two (related) definitions of prominence: The following mental exercise may illustrate the meaning of topographic prominence. Imagine a peak and imagine that an imaginary sea level

neg: Topographic Atlas of Switzerland Another significant departure from the Dufour Map was the presence of contours to symbolize the relief (a granularity of for the 1:25 000 pages, and for the 1:50 000 pages). In addition, three colors were used directly for printing, whereas the Dufour Map was initially monochrome. On the Siegfried Map, the colours used were brown for the contour lines on vegetated terrain, blue for water and contour lines on glaciers, and black for the rest. The Siegfried Map projection was a cone equivalent, as for the Dufour Map. The print mode used for the 1:25,000 pages was initially intaglio, and

neg: Sea level mountains on a topographic map, variations in elevation are shown by contour lines. The elevation of a mountain denotes the highest point or summit and is typically illustrated as a small circle on a topographic map with the AMSL height shown in metres, feet or both. In the rare case that a location is below sea level, the elevation AMSL is negative. For one such case, see Amsterdam Airport Schiphol. To extend this definition far from the sea means comparing the local height of the mean sea surface with a "level" reference surface, or geodetic datum, called the geoid. In

neg: Kloppstert of the same name lie in the Harz near Lerbach and near Badenhausen as well as in the Solling hills southwest of Dassel. Kloppstert The Kloppstert is a hill, roughly 553 metres high, in the southwestern Harz in Lower Saxony, Germany. In the topographical map printed in 1978 it can only be made out with difficulty that the third letter is an "o" and the penultimate one an "r". Unfortunately a contour line runs over the letter "r" so that it looks like a "p". In the digitalised 1:25,000 topographic map, the hill is wrongly named as the "Klappstept". The

neg: Kloppstert Kloppstert The Kloppstert is a hill, roughly 553 metres high, in the southwestern Harz in Lower Saxony, Germany. In the topographical map printed in 1978 it can only be made out with difficulty that the third letter is an "o" and the penultimate one an "r". Unfortunately a contour line runs over the letter "r" so that it looks like a "p". In the digitalised 1:25,000 topographic map, the hill is wrongly named as the "Klappstept". The hill lies about 1 kilometre south of Sieber, 570 metres east of the Fissenkenkopf and 370 metres northwest of the Adlersberg. Other hills

neg: Topography 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 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 is concerned

neg: Horace Kephart spent significant time in Italy as an employee of a wealthy American book collector. In 1904, Kephart's family (wife Laura and their six children) moved to Ithaca, New York, but Laura and Horace never divorced or legally separated. Horace Kephart found his way to western North Carolina, where he lived in the Hazel Creek section of what would later become the Great Smoky Mountains National Park: I took a topographic map and picked out on it, by means of the contour lines and the blank space showing no settlement, what seemed to be the wildest part of these regions; and

neg: Contour line Sometimes a sheen or gloss is used as well as color to set the contour lines apart from the base map. Line colour can be varied to show other information. Line type refers to whether the basic contour line is solid, dashed, dotted or broken in some other pattern to create the desired effect. Dotted or dashed lines are often used when the underlying base map conveys very important (or difficult to read) information. Broken line types are used when the location of the contour line is inferred. Numerical marking is the manner of denoting the arithmetical values of contour

neg: Lake Assal (Djibouti) to the lake, to its southeast, is the Ardoukôka, about away from the shores of the lake, which is marked on topographic map with (-) contour line. The southern part of the lake has sand patches whose width varies from about . There is hardly any arable land in the catchment. The important feature, from the point of view of the sources of water to the lake, is the Assal-Ghoubbet Rift, which is formed of recent basaltic formations (less than 1 Mya). Considering its geological evolution, the lake periphery now has crystal bands of salt and remarkable white gypsum above

neg: Topographic prominence Network Modeling," and is closely related to Morse Theory. Andrew Kirmse extended this method to find every point on Earth with at least 100 feet of prominence. A note about methodology: when using a topographic map to determine prominence, one often has to estimate the height of the key col (and sometimes, the height of the peak as well) based on the contour lines. Assume for simplicity that only the col elevation is uncertain. There are three simple choices. The "pessimistic", or "clean" prominence, assumes that the col is as high as it can be, i.e., its elevation is that

neg: Figure-ground in map design example of using articulation on a map is differentiating a continent from the ocean. The ocean, in most cases, will be the ground and the continent will be the figure. By adding fine-textured shading to water, the continent pops out visually as the figure. Another method that can be employed for articulation is called vignetting, or the inclusion of brightness gradients at the land-water edge. Good contour on the map can be described as the viewer’s ability to continue the line throughout the map. The figure is formed by a contour or outline (as opposed to an isometric contour line),

neg: Contour line elevation difference between adjacent contour lines. The contour interval should be the same over a single map. When calculated as a ratio against the map scale, a sense of the hilliness of the terrain can be derived. There are several rules to note when interpreting terrain contour lines: Of course, to determine differences in elevation between two points, the contour interval, or distance in altitude between two adjacent contour lines, must be known, and this is normally stated in the map key. Usually contour intervals are consistent throughout a map, but there are exceptions. Sometimes intermediate contours are present in

neg: Raised-relief map topographic map, one can cut out successive layers from some sheet material, with edges following the contour lines on the map. These may be assembled in a stack to obtain a rough approximation of the terrain. This method is commonly used as the base for architectural models, and is usually done without vertical exaggeration. For models of landforms, the stack can then be smoothed by filling with some material. This model may be used directly, or for greater durability a mold may be made from it. This mold may then be used to produce a plaster model. A combination of

neg: Mountain pass a ridge). A topographic saddle is analogous to the mathematical concept of a saddle surface, with a saddle point marking the highest point between two valleys and the lowest point along a ridge. On a topographic map, passes are characterized by contour lines with an hourglass shape, which indicates a low spot between two higher points. 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 may be a valley many kilometres long, whose highest point might only

neg: Contour line equal dates of ice formation each winter, and an isotac denotes equal dates of thawing. Contours are one of several common methods used to denote elevation or altitude and depth on maps. From these contours, a sense of the general terrain can be determined. They are used at a variety of scales, from large-scale engineering drawings and architectural plans, through topographic maps and bathymetric charts, up to continental-scale maps. "Contour line" is the most common usage in cartography, but isobath for underwater depths on bathymetric maps and isohypse for elevations are also used. In cartography, the contour interval is the

neg: Geologic map Geologic map A geologic map or geological map is a special-purpose map made to show geological features. Rock units or geologic strata are shown by color or symbols to indicate where they are exposed at the surface. Bedding planes and structural features such as faults, folds, foliations, and lineations are shown with strike and dip or trend and plunge symbols which give these features' three-dimensional orientations. Stratigraphic contour lines may be used to illustrate the surface of a selected stratum illustrating the subsurface topographic trends of the strata. Isopach maps detail the variations in thickness of stratigraphic units. It is

neg: Nicolas F. Shi postage stamp of El Salvador. Nicolas F. Shi Nicolas F. Shi is an artist in Washington, D.C. He is best known for paintings that create an illusion of depth through contour lines like those on a topographic map, with the space between adjacent ones of the contour lines being filled by a single color. A long-time Washington, DC resident, Shi was born in El Salvador to Chinese parents. In 1980, he left his war-torn country and came to the United States to attend college, receiving a master's degree in architectural engineering from Oklahoma State University in 1986. He practiced architecture

neg: Nicolas F. Shi Nicolas F. Shi Nicolas F. Shi is an artist in Washington, D.C. He is best known for paintings that create an illusion of depth through contour lines like those on a topographic map, with the space between adjacent ones of the contour lines being filled by a single color. A long-time Washington, DC resident, Shi was born in El Salvador to Chinese parents. In 1980, he left his war-torn country and came to the United States to attend college, receiving a master's degree in architectural engineering from Oklahoma State University in 1986. He practiced architecture and engineering for more than

neg: Homocline to erosion, their erosion produces either cuestas, homoclinal ridges, or hogbacks depending on the angle of dip of the strata. On a topographic map, the landfroms associated with homoclines exhibit nearly parallel elevation contour lines that show a steady change in elevation in a given direction. In the subsurface, they characterize by parallel structural contour lines. Unicline and Uniclinal are obsolete and currently uncommon terms that are defined and have been used by geologists and geomorphologists in an inconsistent and contradictory manner. They are terms that have been used in a mutually exclusive manner as a synonym for either a

neg: Contour line and hills, and the steepness or gentleness of slopes. The contour interval of a contour map is the difference in elevation between successive contour lines. More generally, a contour line for a function of two variables is a curve connecting points where the function has the same particular value. The gradient of the function is always perpendicular to the contour lines. When the lines are close together the magnitude of the gradient is large: the variation is steep. A level set is a generalization of a contour line for functions of any number of variables. Contour lines are curved, straight

neg: Contour line factors in a weather system. An isobar (from or "baros", meaning 'weight') is a line of equal or constant pressure on a graph, plot, or map; an isopleth or contour line of pressure. More accurately, isobars are lines drawn on a map joining places of equal average atmospheric pressure reduced to sea level for a specified period of time. In meteorology, the barometric pressures shown are reduced to sea level, not the surface pressures at the map locations. The distribution of isobars is closely related to the magnitude and direction of the wind field, and can be used to predict

neg: Cerebral cortex of sensory maps in the cortex reflects that of the corresponding sensing organ, in what is known as a topographic map. Neighboring points in the primary visual cortex, for example, correspond to neighboring points in the retina. This topographic map is called a retinotopic map. In the same way, there exists a tonotopic map in the primary auditory cortex and a somatotopic map in the primary sensory cortex. This last topographic map of the body onto the posterior central gyrus has been illustrated as a deformed human representation, the somatosensory homunculus, where the size of different body parts reflects the

neg: Topographic profile A series of parallel profiles, taken at regular intervals on a map, can be combined to provide a more complete three-dimensional view of the area that appears on the topographic map. It is evident that, thanks to computer science, more sophisticated three-dimensional models of the landscape can be made from digital terrain data. The line of the plane defined by the points that limit the profile is called the guideline and the horizontal line of comparison on which the profile is constructed is called base. One of the most important applications of the topographic profiles is in the construction of

neg: Geologic map new geologic units may be defined). However, in areas where the bedrock is overlain by a significantly thick unconsolidated burden of till, terrace sediments, loess deposits, or other important feature, these are shown instead. Stratigraphic contour lines, fault lines, strike and dip symbols, are represented with various symbols as indicated by the map key. Whereas topographic maps are produced by the United States Geological Survey in conjunction with the states, geologic maps are usually produced by the individual states. There are almost no geologic map resources for some states, while a few states, such as Kentucky and Georgia, are extensively

neg: Contour line density, which can be calculated by dividing the population of a census district by the surface area of that district. Each calculated value is presumed to be the value of the variable at the centre of the area, and isopleths can then be drawn by a process of interpolation. The idea of an isopleth map can be compared with that of a choropleth map. In meteorology, the word "isopleth" is used for any type of contour line. Meteorological contour lines are based on interpolation of the point data received from weather stations and weather satellites. Weather stations are seldom exactly

neg: Map user to toggle decluttering between ON, OFF and AUTO as needed. In AUTO the degree of decluttering is adjusted as the user changes the scale being displayed. Maps of the world or large areas are often either 'political' or 'physical'. The most important purpose of the political map is to show territorial borders; the purpose of the physical is to show features of geography such as mountains, soil type or land use including infrastructure such as roads, railroads and buildings. Topographic maps show elevations and relief with contour lines or shading. Geological maps show not only the physical surface, but

neg: Topographic map that year was commissioned to create a large map, known as "Map of Krayenhoff". Around 1836 they began printing the topographic map on a scale of 1: 50,000, followed in 1865 by the topographic map on a scale of 1: 25,000. In 1951 began the start of production of the topographic map on a scale of 1: 10,000. From various reorganizations arose in 1932 the "Topografische Dienst" as national mapping agency of the Netherlands, since January 2004 housed within the Land Registry "Kadaster". Land Information New Zealand is the government agency responsible for providing up-to-date topographic mapping. LINZ topographic maps

neg: Map symbolization shape of Earth’s surface by using contour lines, the lines on the map that join points of equal elevation. They are among the most well-known symbols on modern maps as they are self-explanatory and accurately represent their phenomena. They make it possible to the depict height, depth, and even slope. Contour lines will be closer together or spaced apart to show the steepness of the area. If the line is spaced closer together, it means that there is a steeper slope. If they are farther apart, the area has a low slope. An area of low slope generally uses contour

neg: Vicmap Topographic Map Series Vicmap Topographic Map Series Vicmap Topographic Map Series is a series of topographic maps covering the State of Victoria, Australia. Created and maintained by the State of Victoria, the map series is currently in a transition phase, with traditional Vicmap Topographic maps being gradually replaced with a new map series. The traditional set of Vicmap Topographic maps consist of approximately 850 1:25000 and 1:50000 hardcopy topographic map sheets printed and made available for sale to the general public. These map sheets cover 80% of Victoria. Most of the mapsheets are single format at a scale of 1:25000. Less inhabited areas

neg: Contour line isotherms in Paris, in 1817. An isogeotherm is a line of equal mean annual temperature. An isocheim is a line of equal mean winter temperature, and an isothere is a line of equal mean summer temperature. An isohel (from or "helios", meaning 'Sun') is a line of equal or constant solar radiation. An isohyet or isohyetal line (from or "huetos", meaning 'rain') is a line joining points of equal rainfall on a map in a given period . A map with isohyets is called an isohyetal map. An isohume is a line of constant relative humidity, while a isodrosotherm (from

neg: Contour line maps, which first appeared in the United States in approximately 1970, largely as a result of national legislation requiring spatial delineation of these parameters. In 2007, Pictometry International was the first to allow users to dynamically generate elevation contour lines to be laid over oblique images. To maximize readability of contour maps, there are several design choices available to the map creator, principally line weight, line color, line type and method of numerical marking. Line weight is simply the darkness or thickness of the line used. This choice is made based upon the least intrusive form of contours that enable

neg: Nepen Diakha Nepen Diakha Nepen Diakha is a locality situated in the Kédougou Region, Senegal. The highest point of the country is located 2.7 km southeast of Nepen Diakha on an unnamed ridge defining the border with Guinea. There is a 648 meters (2,126 feet) above sea level spot height here on the 1983, very detailed, five-meter contour interval 1:25,000 scale topographic map sheet 2049I SE produced by the joint Senegal-Guinea Organization for the Development of the River Gambia with "topography by photogrammetric methods" from US-flown aerial images. SRTM data shows a 642 meter elevation here. The village of Nepin Peul is

neg: Vicmap Topographic Map Series 2008. A4 and A3 size maps covering the entire state of Victoria are currently available to the public online. See link below. Vicmap Topographic Map Series Vicmap Topographic Map Series is a series of topographic maps covering the State of Victoria, Australia. Created and maintained by the State of Victoria, the map series is currently in a transition phase, with traditional Vicmap Topographic maps being gradually replaced with a new map series. The traditional set of Vicmap Topographic maps consist of approximately 850 1:25000 and 1:50000 hardcopy topographic map sheets printed and made available for sale to the general public.

neg: Nepen Diakha the closest locality to this ridge. The coordinates of the highest point of Senegal are . Nepen Diakha Nepen Diakha is a locality situated in the Kédougou Region, Senegal. The highest point of the country is located 2.7 km southeast of Nepen Diakha on an unnamed ridge defining the border with Guinea. There is a 648 meters (2,126 feet) above sea level spot height here on the 1983, very detailed, five-meter contour interval 1:25,000 scale topographic map sheet 2049I SE produced by the joint Senegal-Guinea Organization for the Development of the River Gambia with "topography by photogrammetric methods" from US-flown

neg: Survey camp form contour lines and thus a topographic map of an area is prepared using AutoCAD or with the help of plane table survey. In Survey camp, students obtain extensive hands-on experience in the use of land surveying instruments and in the essentials of survey practice. Measurements of distances and angles, calculation and correction of errors are introduced. Concepts of higher order surveys and satellite navigation are reviewed and illustrated. Thus students learn surveying practically, this gives them confidence to work (with good precision and accuracy) in Industrial fields in the future. Survey camp Survey Camp is an army tradition that

neg: Contour line Isoclines are used to solve ordinary differential equations. In interpreting radar images, an isodop is a line of equal Doppler velocity, and an isoecho is a line of equal radar reflectivity. The idea of lines that join points of equal value was rediscovered several times. The oldest known isobath (contour line of constant depth) is found on a map dated 1584 of the river Spaarne, near Haarlem, by Dutchman Pieter Bruinsz. In 1701, Edmond Halley used such lines (isogons) on a chart of magnetic variation. The Dutch engineer Nicholas Cruquius drew the bed of the river Merwede with lines of

neg: Scalar potential and let Δ"x" be the distance between two contours. Then so that However, on a contour map, the gradient is inversely proportional to Δ"x", which is not similar to force "F": altitude on a contour map is not exactly a two-dimensional potential field. The magnitudes of forces are different, but the directions of the forces are the same on a contour map as well as on the hilly region of the Earth's surface represented by the contour map. In fluid mechanics, a fluid in equilibrium, but in the presence of a uniform gravitational field is permeated by a uniform buoyant

neg: Contour line different elevations, for example, living on different floor levels of an urban apartment. In actuality, both plan and profile view contour maps are used in air pollution and noise pollution studies. Labels are a critical component of elevation maps. A properly labeled contour map helps the reader to quickly interpret the shape of the terrain. If numbers are placed close to each other, it means that the terrain is steep. Labels should be placed along a slightly curved line "pointing" to the summit or nadir, from several directions if possible, making the visual identification of the summit or nadir easy.

neg: Kilkenny, New Hampshire of Kilkenny as a line extending the northern border of Jefferson and Lancaster (1872 Railroad and Post Office Map of New Hampshire, and 1892 map of Jefferson). The 1896 topographic map, however, shows that the boundary had again been adjusted several miles south, to include Mount Waumbek and Pliny Mountain, uninhabited areas. Deeds in this area often refer to the "Kilkenny Addition". On the 1935 topographic map, the "Upper Ammonoosuc Trail" crossed Kilkenny along Priscilla Brook and through the pass from the Keenan Brook area of Randolph, north of Pliny Mountain. This trail has since been abandoned, although a 2002

neg: Field line Field line A field line is a locus that is defined by a vector field and a starting location within the field. Field lines are useful for visualizing vector fields, which are otherwise hard to depict. Unlike longitude and latitude lines on a globe, or topographic lines on a topographic map, they are not physically present at any locations; they are merely conceptual tools. A vector field defines a direction at all points in space; a field line for that vector field may be constructed by tracing a path (possibly a loop) through space that follows the direction of the

neg: Contour line or "drosos", meaning 'dew', and or "therme", meaning 'heat') is a line of equal or constant dew point. An isoneph is a line indicating equal cloud cover. An isochalaz is a line of constant frequency of hail storms, and an isobront is a line drawn through geographical points at which a given phase of thunderstorm activity occurred simultaneously. Snow cover is frequently shown as a contour-line map. An isotach (from or "tachus", meaning 'fast') is a line joining points with constant wind speed. In meteorology, the term isogon refers to a line of constant wind direction. An isopectic line denotes

neg: United States Geological Survey for these maps; the 30 x 60-minute quadrangle series. Each of these quadrangles covers the area contained within 32 maps in the 7.5-minute series. The 1:100,000 scale series is unusual in that it employs the Metric system primarily. One centimeter on the map represents one kilometer of distance on the ground. Contour intervals, spot elevations, and horizontal distances are also specified in meters. The final regular quadrangle series produced by the USGS is the 1:250,000 scale topographic series. Each of these quadrangles in the conterminous United States measures 1 degree of latitude by 2 degrees of longitude. This series was

neg: Swisstopo de Genève". Topographic surveys also started in the alpine regions of Switzerland. These had their first results in 1845, a year later than planned, when a map scaled 1:100.000 was published. This was the start of what are termed "Dufourkarten" ("Dufour's Maps"). The topographic survey finished in 1862. To honour Dufour, the Swiss government decided to rename the highest peak on the "Dufourkarten" from "Höchste Spitze" to Dufourspitze: it still carries that name today. In 1863, the SAC published a 1:50.000 map of the region Tödi, based on unpublished survey material. A year later, the last map of the "Dufourkarten"

neg: Geographic information system toxic spill. Traditional maps are abstractions of the real world, a sampling of important elements portrayed on a sheet of paper with symbols to represent physical objects. People who use maps must interpret these symbols. Topographic maps show the shape of land surface with contour lines or with shaded relief. Today, graphic display techniques such as shading based on altitude in a GIS can make relationships among map elements visible, heightening one's ability to extract and analyze information. For example, two types of data were combined in a GIS to produce a perspective view of a portion of San Mateo

neg: Contour line equal depth (isobaths) at intervals of 1 fathom in 1727, and Philippe Buache used them at 10-fathom intervals on a chart of the English Channel that was prepared in 1737 and published in 1752. Such lines were used to describe a land surface (contour lines) in a map of the Duchy of Modena and Reggio by Domenico Vandelli in 1746, and they were studied theoretically by Ducarla in 1771, and Charles Hutton used them in the Schiehallion experiment. In 1791, a map of France by J. L. Dupain-Triel used contour lines at 20-metre intervals, hachures, spot-heights and a vertical section.

neg: Stereoplotter too far away from a slope or too far toward a slope, respectively. Originally, stereoplotters recorded the path of the flying light spot by directly scribing the path on a sheet of acetate or polyester coated with an opaque lacquer, which could be photographed to make the topographic map printing plates. If mistakes were made during contour tracing, the operator would daub some lacquer on the incorrect trace, allow it to dry and then try flying the light spot again. Current systems that use digital capture techniques allow simple erasure of part of the faulty data vector in computer memory,

neg: Thematic map retained, but gaps appear between units. Isarithmic maps, also known as contour maps or isoline maps depict smooth continuous phenomena such as precipitation or elevation. Each line-bounded area on this type of map represents a region with the same value. For example, on an elevation map, each elevation line indicates an area at the listed elevation. An Isarithmic map is a planimetric graphic representation of a 3-D surface. Isarithmic mapping requires 3-D thinking for surfaces that vary spatially. A dot distribution map might be used to locate each occurrence of a phenomenon, as in the map made by Dr. Snow

neg: Sliding mode control surface is reached in finite time. Once a trajectory reaches the surface, it will slide along it and may, for example, move toward the formula_25 origin. So the switching function is like a topographic map with a contour of constant height along which trajectories are forced to move. The sliding (hyper)surface is of dimension formula_26 where is the number of states in formula_13 and is the number of input signals (i.e., control signals) in formula_10. For each control index formula_29, there is an formula_30 sliding surface given by The vital part of SMC design is to choose a control law

neg: Hypanartia lethe Hypanartia lethe Hypanartia lethe, the orange admiral or orange mapwing, is a butterfly of the family Nymphalidae. "Hypanartia lethe" has a wingspan of about . Forewings are black with orange-brown spots and an orange-brown fascia composed by a few blotches. Hindwings are orange brown, with a row of black spots in the marginal area and a black narrow strip in the submarginal area near the apex. The underside of the wings shows an ornate pattern and a pale brown coloration resembling the contour lines of a topographic map (hence the common name orange mapwing). Adults have two hindwing tails of

neg: Topographic wetness index of computing this index differ primarily in the way the upslope contributing area is calculated. The topographic wetness index is defined as: formula_1 where formula_2 is the local upslope area draining through a certain point per unit contour length and formula_3 is the local slope in radians. The TWI has been used to study spatial scale effects on hydrological processes. The topographic wetness index (TWI) was developed by Beven and Kirkby within the runoff model TOPMODEL. The topographic wetness index is unitless. The TWI has been used to study spatial scale effects on hydrological processes and to identify hydrological flow

neg: LASIK corneal topography machine, to measure their surface contour. Using low-power lasers, a topographer creates a topographic map of the cornea. The procedure is contraindicated if the topographer finds difficulties such as keratoconus The preparatory process also detects astigmatism and other irregularities in the shape of the cornea. Using this information, the surgeon calculates the amount and the location of corneal tissue to be removed. The patient is prescribed and self-administers an antibiotic beforehand to minimize the risk of infection after the procedure and is sometimes offered a short acting oral sedative medication as a pre-medication. Prior to the procedure, anaesthetic

neg: Contour line flatter areas; these can be dashed or dotted lines at half the noted contour interval. When contours are used with hypsometric tints on a small-scale map that includes mountains and flatter low-lying areas, it is common to have smaller intervals at lower elevations so that detail is shown in all areas. Conversely, for an island which consists of a plateau surrounded by steep cliffs, it is possible to use smaller intervals as the height increases. An isopotential map is a measure of electrostatic potential in space, often depicted in two dimensions with the electostatic charges inducing that electric potential. The

neg: Contour line lines. This can be done by placing numbers along some of the contour lines, typically using interpolation for intervening lines. Alternatively a map key can be produced associating the contours with their values. If the contour lines are not numerically labeled and adjacent lines have the same style (with the same weight, color and type), then the direction of the gradient cannot be determined from the contour lines alone. However, if the contour lines cycle through three or more styles, then the direction of the gradient can be determined from the lines. The orientation of the numerical text labels is

neg: Topographic Map of Switzerland Topographic Map of Switzerland The Topographic Map of Switzerland (German: "Topographische Karte der Schweiz"), also known as the Dufour Map (German: "Dufourkarte"; French: "Carte Dufour") is a 1:100 000 scale map series depicting Switzerland for the first time based on accurate geometric measurements. It is also the oldest official map series of Switzerland. From 1796 to 1802, the "Atlas Suisse" was published in Aarau by Johann Heinrich Weiss, Johann Rudolf Meyer and Joachim Eugen Müller. The "Atlas Suisse" map series consisted of 16 sheets, was produced by a copperplate or intaglio printing process, and depicted the whole of Switzerland at

neg: Contour line height on a constant pressure surface chart. Isohypse and isoheight are simply known as lines showing equal pressure on a map. An isotherm (from or "thermē", meaning 'heat') is a line that connects points on a map that have the same temperature. Therefore, all points through which an isotherm passes have the same or equal temperatures at the time indicated. An isotherm at 0 °C is called the freezing level. The term was coined by the Prussian geographer and naturalist Alexander von Humboldt, who as part of his research into the geographical distribution of plants published the first map of

neg: Topography 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 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

neg: Topographic Atlas of Switzerland Topographic Atlas of Switzerland The Topographic Atlas of Switzerland (German: "Topographischer Atlas der Schweiz"), also known as the "Siegfried Atlas" or Siegfried Map (German: "Siegfriedkarte"; French: "Carte Siegfried") is an official map series of Switzerland. Its publication was begun by the Federal Topographic Bureau under Hermann Siegfried, and continued from 1870 to 1922. During this period the individual maps were drawn by different lithographers, including Walter Hauenstein, Georg Christian von Hoven and Rudolf Leuzinger. Since it is, in today's parlance, not strictly an atlas but a map series, map historians now describe it only by the expression "Siegfried Map". The

neg: Terrain cartography relief was standardized by the Austrian topographer Johann Georg Lehmann in 1799. Contour lines (or isohypses) are isolines showing equal elevation. This is the most common way of numerically showing elevation, and is familiar from topographic maps. Most 18th and early 19th century national surveys did not record relief across the entire area of coverage, calculating only spot elevations at survey points. The United States Geological Survey (USGS) topographical survey maps included contour representation of relief, and so maps that show relief, especially with exact representation of elevation, came to be called topographic maps (or "topo" maps) in the United

neg: Contour line or a mixture of both lines on a map describing the intersection of a real or hypothetical surface with one or more horizontal planes. The configuration of these contours allows map readers to infer relative gradient of a parameter and estimate that parameter at specific places. Contour lines may be either traced on a visible three-dimensional model of the surface, as when a photogrammetrist viewing a stereo-model plots elevation contours, or interpolated from estimated surface elevations, as when a computer program threads contours through a network of observation points of area centroids. In the latter case, the method of interpolation

neg: Scalar potential of the reference point formula_13 An example is the (nearly) uniform gravitational field near the Earth's surface. It has a potential energy where "U" is the gravitational potential energy and "h" is the height above the surface. This means that gravitational potential energy on a contour map is proportional to altitude. On a contour map, the two-dimensional negative gradient of the altitude is a two-dimensional vector field, whose vectors are always perpendicular to the contours and also perpendicular to the direction of gravity. But on the hilly region represented by the contour map, the three-dimensional negative gradient of "U" always

neg: Generative topographic map Generative topographic map Generative topographic map (GTM) is a machine learning method that is a probabilistic counterpart of the self-organizing map (SOM), is probably convergent and does not require a shrinking neighborhood or a decreasing step size. It is a generative model: the data is assumed to arise by first probabilistically picking a point in a low-dimensional space, mapping the point to the observed high-dimensional input space (via a smooth function), then adding noise in that space. The parameters of the low-dimensional probability distribution, the smooth map and the noise are all learned from the training data using the expectation-maximization

neg: Topographic Map of Switzerland editions of the Dufour Map give a reliable overview of demographic trends in Switzerland, the extension of settlements and significant changes in the territory, such as the damming of rivers, the construction of roads, and railway development. From 1870, a map series in the 1:25,000 scale of the original Dufour Map images was published under the official name Topographic Atlas of Switzerland (German: "Topographischer Atlas der Schweiz"), and also known as the "Siegfried Atlas" or Siegfried Map (German: "Siegfriedkarte"; French: "Carte Siegfried"). Topographic Map of Switzerland The Topographic Map of Switzerland (German: "Topographische Karte der Schweiz"), also known as the

neg: Wojskowy Instytut Geograficzny by the partitioning powers (German, Russian and Austro-Hungarian Empires). The maps in various scales were the foundation of the 1:100,000 scale Polish maps. By 1926 40% of the area of Poland was mapped. From 1927 onwards, WIG began to draw a uniform triangulation network and to print its own, original 1: 100,000 map, known as “type two”. These maps were two-coloured (black topographic elements, brown contour lines), some sheets contained two more colours added by overprinting. From 1929 onwards “type three”, i.e. two- and four-coloured maps were published. In 1931 a four-colour version became the standard type (known as “normal

neg: Figure-ground in map design the common boundary between the figure and ground, usually through a brightness contrast. If a figure is not separated entirely from the ground, a simple black contour line can be drawn around the figure enclosing it and thus differentiating it from the ground. Intellectual hierarchy, also known as a scale of concepts, refers to the idea that some map features are more important than others. The placement on a map or the ordering of information will convey relative importance of map features to the percipient. If developed on the map correctly, the intellectual hierarchy will correspond to the visual hierarchy

neg: Topographic Atlas of Switzerland from 1905 a printing plate. The 1:50,000 pages were printed via a lithography process, and from 1910 by intaglio. Until 1949, there were occasional revised editions of Siegfried Map pages. From 1952, the Siegfried and Dufour Maps were replaced by the new National Map of Switzerland. Topographic Atlas of Switzerland The Topographic Atlas of Switzerland (German: "Topographischer Atlas der Schweiz"), also known as the "Siegfried Atlas" or Siegfried Map (German: "Siegfriedkarte"; French: "Carte Siegfried") is an official map series of Switzerland. Its publication was begun by the Federal Topographic Bureau under Hermann Siegfried, and continued from 1870 to 1922. During

neg: Mao Kun map been suggested by J.J.L. Duyvendak and Paul Pelliot that the map may have been partly based on Arab nautical charts. The map was originally in the form of a strip map of 20.5 cm by 560 cm that could be rolled up, but was then divided into 40 pages in the book. The map, after Nanjing and the Yangtze River, shows mainly the coastal regions and islands along the sea route, and places are depicted in their approximate positions along the contour of the coast. The coast of the main land mass is shown largely as a continuous irregular line

neg: Cross section (geometry) Cross section (geometry) In geometry and science, a cross section is the non-empty intersection of a solid body in three-dimensional space with a plane, or the analog in higher-dimensional spaces. Cutting an object into slices creates many parallel cross sections. The boundary of a cross section in three-dimensional space that is parallel to two of the axes, that is, parallel to the plane determined by these axes, is a sometimes referred to as a contour line; for example, if a plane cuts through mountains of a raised-relief map parallel to the ground, the result is a contour line in two-dimensional

neg: The National Map of volunteers who devote some of their time to provide cartographic information on structures. "The National Map" is the official replacement for the USGS topographic map program. The National Map The National Map is a collaborative effort of the United States Geological Survey (USGS) and other federal, state, and local agencies to improve and deliver topographic information for the United States. The purpose of the effort is to provide "...a seamless, continuously maintained set of public domain geographic base information that will serve as a foundation for integrating, sharing, and using other data easily and consistently". "The National Map" is

neg: Effect of gait parameters on energetic cost can be expressed in the form of a contour map, in which parameter combinations that lie on the same contour line share the same cost of transport (cal/kg/m). The green, red, and blue, dotted lines represent values where cadence, walking speed, and step length are constrained, respectively. These lines can be formed by finding the tangent points that lines representative of several constant parameter values form with the constant COT contours. For example, the optimal COT's for constrained walking speeds (red) can be found by drawing vertical lines and noting where they form a tangent with a contour, as seen

neg: Hoodoo Mountain makes Hoodoo Mountain different from other neighbouring mountains in the Boundary Ranges. The volcano boasts an ice cap on its summit, and radar imaging of the rock beneath the ice has shown that the mountain's flat-topped summit is not just attributable to the ice cap, but the top of the mountain is flat as well. Beneath the summit ice cap lies an ice-filled volcanic crater that rises at an elevation of and a topographic prominence of . Except for minor irregularities caused by erosion, any contour line drawn is practically a circle. Hoodoo Mountain consists of a balanced lava dome

neg: Generative topographic map model. Thus, it has a number of advantages over SOM, namely: GTM was introduced by Bishop, Svensen and Williams in their Technical Report in 1997 (Technical Report NCRG/96/015, Aston University, UK) published later in Neural Computation. It was also described in the PhD thesis of Markus Svensen (Aston, 1998). Generative topographic map Generative topographic map (GTM) is a machine learning method that is a probabilistic counterpart of the self-organizing map (SOM), is probably convergent and does not require a shrinking neighborhood or a decreasing step size. It is a generative model: the data is assumed to arise by first probabilistically

neg: Topographic map (neuroanatomy) Topographic map (neuroanatomy) A topographic map is the ordered projection of a sensory surface, like the retina or the skin, or an effector system, like the musculature, to one or more structures of the central nervous system. Topographic maps can be found in all sensory systems and in many motor systems. The visual system refers to the part of the central nervous system that allows an organism to see. It interprets information from visible light to build a representation of the world. The ganglion cells of the retina project in an orderly fashion to the lateral geniculate nucleus of the

neg: Libre Map Project on DVDs for $1600 to make the data available. Additional data made available through the project includes SVG boundary files for every US state, Topologically Integrated Geographic Encoding and Referencing (Tiger)/Line 2003 vector map data, and the USGS GeoNames database. Libre Map Project The Libre Map Project is an 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. The Libre Map Project was started by Jared Benedict and around 100 additional individuals contributing money to purchase (or "liberate") a full set of 1:24K

neg: Topographic map all topographic control, surveys and mapping of India. The Survey of Israel is responsible for the civilian mapping of Israel. Standard map scales are 1:50,000 and 1:100,000. The 1:50,000 map is available online. Israel is the country where many high elevation places are there. The Military Intelligence Directorate of the Israeli defense forces has its own mapping unit, which is a sub-unit of Unit 9900. The Geographical Survey Institute of Japan is responsible for base mapping of Japan. Standard map scales are 1:25,000, 1:50,000, 1:200,000 and 1:500,000. From 1992 to 2002 a definitive series of large scale topographic maps were

neg: Balsam Lake Mountain Balsam Lake Mountain Balsam Lake Mountain is one of the Catskill Mountains, located in the Town of Hardenburgh, New York, United States. It is the westernmost of the range's 35 High Peaks. Its exact height has not been determined, but the highest contour line on topographic maps, , is usually given as its elevation. Located within the Balsam Lake Mountain Wild Forest management unit of the Catskill Park Forest Preserve, in the late 19th century its summit became the site of the first fire lookout tower in the state, operated by members of a nearby sportsmen's club. It was later

neg: Topographic map Nevertheless, national mapping programs listed below are only a partial selection. Several commercial vendors supply international topographic map series. The NMIG (National Mapping Information Group) of Geoscience Australia is the Australian Government's national mapping agency. It provides topographic maps and data to meet the needs of the sustainable development of the nation. The Office of Spatial Data Management provides an online free map service MapConnect. These topographic maps of scales 1:250,000 and 1:100,000 are available in printed form from the Sales Centre. 1:50,000 and 1:25,000 maps are produced in conjunction with the Department of Defence. "Austrian Maps" () is the

neg: Scientific Computer Applications Scientific Computer Applications Scientific Computer Applications, Inc. (SCAI) was established in 1969 as an Oil & Gas Consulting firm by Professional engineering Petroleum Consultant Richard Banks, a graduate of the Colorado School of Mines and the University of Texas. SCAI markets contour map software that generates single surface, multiple surface, contour mapping and Reservoir Integration applications for the Personal computer. Dick Banks, a Colorado School of Mines graduate, and Joe Sukkar, Ph.D, began a partnership in 1969 with the development of a contour mapping software package based on Triangulation (topology). Triangulation is more rigorous than gridded contour map software because

neg: Topographic map of 2011, the future of standardized, centrally printed topographical maps is left somewhat in doubt. Topographic maps have 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. 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 the margin of the map, or on a separately published characteristic sheet. Topographic maps

neg: Mount Shishaldin Mount Shishaldin Mount Shishaldin is a moderately active volcano on Unimak Island in the Aleutian Islands chain of Alaska. It is the highest mountain peak of the Aleutian Islands. The most symmetrical cone-shaped glacier-clad large mountain on earth, the volcano's topographic contour lines are nearly perfect circles above . The lower north and south slopes are somewhat steeper than the lower eastern and western slopes. The volcano is the westernmost of three large stratovolcanoes along an east–west line in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am

neg: Solar map Solar map A solar map, in general, is a map of a city, state, country, or any piece of land that illustrates information about how much a certain piece of land, building, or home experiences a certain amount of sunlight. Though solar maps are illustrated in many forms, a solar map essentially records where and to what extent a certain location experiences a certain amount of sunlight or radiation. It normally combines topographic, meteorological, and sometimes financial data to help scholars or consumers and investors in promoting awareness of the potential of solar power. Solar maps come in a variety

neg: Topographic map producing and distributing topographic maps of Colombia in 1:500,000 and 1:100,000 scales. These and several other Geographic information services can be accessed using the Instituto Geográfico Agustin Codazzi website in Spanish. The National Survey and Cadastre of Denmark is responsible for producing topographic and nautical geodata of Denmark, Greenland and the Faroe Islands. The National Land Survey of Finland produces the Topographic Database (accuracy 1:5000-1:10 000) and publishes topographic maps of Finland at 1:25,000 and 1:50,000. In addition topographics maps can be viewed by using a free map service MapSite. The Institut Géographique National (IGN) produces topographic maps of France

neg: Transcription (music) found here. This in turn leads to a “pitch contour” namely a continuously time-varying line that corresponds to what humans refer to as melody. The next step is to segment this continuous melodic stream to identify the beginning and end of each note. After that each “note unit” is expressed in physical terms (e.g., 442 Hz, .52 seconds). The final step is then to map this physical information into familiar music-notation-like terms for each note (e.g., an A4, quarter note). In terms of actual computer processing, the principal steps are to 1) digitize the performed, analog music, 2) do successive

neg: Bermuda Pedestal Bermuda Pedestal The Bermuda Pedestal is an oval-shaped geological feature in the northern Atlantic Ocean containing the topographic highs of the Bermuda Platform, the Plantagenet (Argus) Bank, and the Challenger Bank. The pedestal is long and wide at the 100 fathom line (-185 m), while the base measures 130 km by 80 km at -4200 m. Surrounding the pedestal is a much larger mid-basin swell known as the Bermuda Rise, measuring 900 km by 600 km at the 5000 m depth contour. The islands of Bermuda are located on the southeastern margin of the Bermuda Pedestal. The oceanic crust surrounding

neg: Calmont (hill) "Cochemer Krampen" (250.33). It terrain descends to the north into the Ellerbach valley, to the northwest and west and, ascending to the west-southwest to the Schafstall, into the natural region of "Gevenicher Hochfläche" (270.02), which is part of major unit group of the East Eifel (27), major unit of the Moselle Eifel (270) and sub-unit of the Eastern Moselle Eifel ("Östliche Moseleifel", 270.0). The -high Calmont summit lies 293.1 metres above the Moselle, on which the lowest contour line on topographic maps is . It is also an average of about 270 metres above Bremm. Around 215 metres east-northeast of

neg: Lehigh Valley Transit Company biking. A right of way culvert and pole line are at Koffel Street close to the end of Squirrel Lane where the LVT entered Lansdale. Wales Junction: The original 1900 LVT trolley line to Chestnut Hill and the newer interurban line to Norristown met at Wales Junction at the Sumneytown Pike and Reading railroad. Map: Some of the former LVT right of way is visible from satellite as a faint scar across the countryside north of Quakertown to Summit Lawn. The DeLorme Company's "Pennsylvania Atlas and Gazetteer Topographic Map" shows "old railroad grades." The abandoned LVT is shown running from

neg: Geographic information system television stations, and schools. 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. Many sophisticated methods can estimate the characteristics of surfaces from a limited number of point measurements. A two-dimensional contour map created from the surface modeling of rainfall point measurements may be overlaid and analyzed with any other map in a GIS covering