In modern mapping, a topographic map is a type of map characterized by large-scale detail and quantitative representation of relief using contour lines, but using a variety of methods. Traditional definitions require a topographic map to show both man-made features. A topographic survey is 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:These maps depict in detail ground relief, forest cover, administrative areas, populated areas, transportation routes and facilities, other man-made features. Other authors define topographic maps by contrasting them with another type of map. However, in the vernacular and day to day world, the representation of relief is popularly held to define the genre, such that small-scale maps showing relief are called "topographic"; the study or discipline of topography is a much broader field of study, which takes into account all natural and man-made features of terrain.
Topographic maps are based on topographical surveys. Performed at large scales, these surveys are called topographical in the old sense of topography, showing a variety of elevations and landforms; this is in contrast to older cadastral surveys, which show property and governmental boundaries. The first multi-sheet topographic map series of an entire country, the Carte géométrique de la France, was completed in 1789; the Great Trigonometric Survey of India, started by the East India Company in 1802 taken over by the British Raj after 1857 was notable as a successful effort on a larger scale and for determining heights of Himalayan peaks from viewpoints over one hundred miles distant. Topographic surveys were prepared by the military to assist in planning for battle and for defensive emplacements; as such, elevation information was of vital importance. As they evolved, topographic map series became a national resource in modern nations in planning infrastructure and resource exploitation. In the United States, the national map-making function, shared by both the Army Corps of Engineers and the Department of the Interior migrated to the newly created United States Geological Survey in 1879, where it has remained since.1913 saw the beginning of the International Map of the World initiative, which set out to map all of Earth's significant land areas at a scale of 1:1 million, on about one thousand sheets, each covering four degrees latitude by six or more degrees longitude.
Excluding borders, each sheet was up to 66 cm wide. Although the project foundered, it left an indexing system that remains in use. By the 1980s, centralized printing of standardized topographic maps began to be superseded by databases of coordinates that could be used on computers by moderately skilled end users to view or print maps with arbitrary contents and scale. For example, the Federal government of the United States' TIGER initiative compiled interlinked databases of federal and local political borders and census enumeration areas, of roadways and water features with support for locating street addresses within street segments. TIGER was used in the 1990 and subsequent decennial censuses. Digital elevation models were compiled from topographic maps and stereographic interpretation of aerial photographs and from satellite photography and radar data. Since all these were government projects funded with taxes and not classified for national security reasons, the datasets were in the public domain and usable without fees or licensing.
TIGER and DEM datasets facilitated Geographic information systems and made the Global Positioning System much more useful by providing context around locations given by the technology as coordinates. Initial applications were professionalized forms such as innovative surveying instruments and agency-level GIS systems tended by experts. By the mid-1990s user-friendly resources such as online mapping in two and three dimensions, integration of GPS with mobile phones and automotive navigation systems appeared; as of 2011, the future of standardized, centrally printed topographical maps is left somewhat in doubt. Topographic maps have multiple uses in the present day: any type of geographic planning or large-scale architecture; the various features shown on the map are represented by conventional symbols. For example, colors can be used to indicate a classification of roads; these signs are explained in the margin of the map, or on a separately published characteristic sheet. Topographic maps are 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 called topo quads or quadrangles. Topographic maps conventionally show land contours, by means of contour lines. Contour lines are curves. In other words, every point on the marked line of 100 m elevation is 100 m above mean sea level; these maps show
Ysgafell Wen North Top
Ysgafell Wen North Top is a peak on a ridge in Snowdonia, North Wales. It lies to the north of the highest summit on the ridge Ysgafell Wen, it is a subsidiary summit of Allt-fawr. The summit is located at the edge of an edge that falls steeply into the cwm. Small lakes surround the summit, known as Llynnau'r Cwn. To the west lies the peak's top, known as Ysgafell Wen Far North Top. www.geograph.co.uk: photos of Ysgafell Wen and surrounding area
Ordnance Survey is the national mapping agency of the United Kingdom which covers the island of Great Britain. Since 1 April 2015 part of Ordnance Survey has operated as Ordnance Survey Ltd, a government-owned company, 100% in public ownership; the Ordnance Survey Board remains accountable to the Secretary of State for Business and Industrial Strategy. It is a member of the Public Data Group; the agency's name indicates its original military purpose, to map Scotland in the wake of the Jacobite rising of 1745. There was a more general and nationwide need in light of the potential threat of invasion during the Napoleonic Wars. Ordnance Survey mapping is classified as either "large-scale" or "small-scale"; the Survey's large-scale mapping comprises 1:2,500 maps for 1:10,000 more generally. These large scale maps are used in professional land-use contexts and were available as sheets until the 1980s, when they were digitised. Small-scale mapping for leisure use includes the 1:25,000 "Explorer" series, the 1:50,000 "Landranger" series and the 1:250,000 road maps.
These are still available in traditional sheet form. Ordnance Survey maps remain in copyright for fifty years after their publication; some of the Copyright Libraries hold complete or near-complete collections of pre-digital OS mapping. The origins of the Ordnance Survey lie in the aftermath of the Jacobite rising of 1745, defeated by forces loyal to the government at the Battle of Culloden in 1746. Prince William, Duke of Cumberland realised that the British Army did not have a good map of the Scottish Highlands to locate Jacobite dissenters such as Simon Fraser, 11th Lord Lovat so that they could be put on trial. In 1747, Lieutenant-Colonel David Watson proposed the compilation of a map of the Highlands to help to subjugate the clans. In response, King George II charged Watson with making a military survey of the Highlands under the command of the Duke of Cumberland. Among Watson's assistants were William Roy, Paul Sandby and John Manson; the survey was produced at a scale of 1 inch to 1000 yards and included "the Duke of Cumberland's Map", now held in the British Library.
Roy had an illustrious career in the Royal Engineers, rising to the rank of General, he was responsible for the British share of the work in determining the relative positions of the French and British royal observatories. This work was the starting point of the Principal Triangulation of Great Britain, led to the creation of the Ordnance Survey itself. Roy's technical skills and leadership set the high standard. Work was begun in earnest in 1790 under Roy's supervision, when the Board of Ordnance began a national military survey starting with the south coast of England. Roy's birthplace near Carluke in South Lanarkshire is today marked by a memorial in the form of a large OS trig point. By 1791 the Board received the newer Ramsden theodolite, work began on mapping southern Great Britain using a five-mile baseline on Hounslow Heath that Roy himself had measured. In 1991 Royal Mail marked the bicentenary by issuing a set of postage stamps featuring maps of the Kentish village of Hamstreet. In 1801 the first one-inch-to-the-mile map was published, detailing the county of Kent, with Essex following shortly afterwards.
The Kent map was published and stopped at the county border, while the Essex maps were published by Ordnance Survey and ignore the county border, setting the trend for future Ordnance Survey maps. In the next 20 years about a third of England and Wales was mapped at the same scale under the direction of William Mudge, as other military matters took precedence, it took until 1823 to re-establish a relationship with the French survey made by Roy in 1787. By 1810 one inch to the mile maps of most of the south of England were completed, but they were withdrawn from sale between 1811 and 1816 because of security fears. By 1840 the one-inch survey had covered all of Wales and all but the six northernmost counties of England, it was hard work: Major Thomas Colby, the longest-serving Director General of Ordnance Survey, walked 586 miles in 22 days on a reconnaissance in 1819. In 1824, Colby and most of his staff moved to Ireland to work on a six-inches-to-the-mile valuation survey; the survey of Ireland, county by county, was completed in 1846.
The suspicions and tensions it caused in rural Ireland are the subject of Brian Friel's play Translations. Colby was not only involved in the design of specialist measuring equipment, he established a systematic collection of place names, reorganised the map-making process to produce clear, accurate plans. Place names were recorded in "Name Books", a system first used in Ireland; the instructions for their use were: The persons employed on the survey are to endeavour to obtain the correct orthography of the names of places by diligently consulting the best authorities within their reach. The name of each place is to be inserted as it is spelt, in the first column of the name book and the various modes of spelling it used in books, writings &c. are to be inserted in the second column, with the authority placed in the third column opposite to each. Whilst these procedures produced excellent results, mistakes were made: for instance, the Pilgrims Way in the North Downs labelled the wrong route
A ridge or a mountain ridge is a geological feature consisting of a chain of mountains or hills that form a continuous elevated crest for some distance. The sides of the ridge slope away from narrow top on either side; the line along the crest formed by the highest points, with the terrain dropping down on either side, is called the ridgeline. Ridges are termed hills or mountains as well, depending on size. There are several main types of ridges: Dendritic ridge: In typical dissected plateau terrain, the stream drainage valleys will leave intervening ridges; these are by far the most common ridges. These ridges represent more erosion resistant rock, but not always – they remain because there were more joints where the valleys formed or other chance occurrences; this type of ridge is somewhat random in orientation changing direction often with knobs at intervals on the ridge top. Stratigraphic ridge: In places such as the Ridge-and-Valley Appalachians, long straight ridges are formed because they are the uneroded remaining edges of the more resistant dipping strata that were folded laterally.
Similar ridges have formed in places such as the Black Hills, where the ridges form concentric circles around the igneous core. Sometimes these ridges are called "hogback ridges". Oceanic spreading ridge: In tectonic spreading zones around the world, such as at the Mid-Atlantic Ridge, the volcanic activity forms new land between tectonic boundaries creating volcanic ridges at the spreading zone. Isostatic settling and erosion reduces the elevations moving away from the zone. Crater ridges: Large meteorite strikes form large impact craters bordered by circular ridges. Volcanic crater/caldera ridges: Large volcanoes leave behind a central crater/caldera bordered by circular ridges. Fault ridges: Faults form escarpments. Sometimes the tops of the escarpments form not plateaus but slope back so that the edges of the escarpments form ridges. Dune ridges: In areas of large-scale dune activity, certain types of dunes result in sand ridges. Moraines and eskers: Glacial activity may leave ridges in the form of moraines and eskers.
An arête is a thin ridge of rock, formed by glacial erosion. Volcanic subglacial ridges: Many subglacial volcanoes create ridge-like formations when lava erupts through a thick glacier or ice sheet. Shutter ridges: A shutter ridge is a ridge which has moved along a fault line, blocking or diverting drainage. A shutter ridge creates a valley corresponding to the alignment of the fault that produces it. Pressure ridges: Also known as a tumuli develops in lava flows when slow-moving lava beneath a solidified crust wells upward; the brittle crust buckles to accommodate the inflating core of the flow, thus creating a central crack along the length of the tumulus. An Ice pressure ridge develops in an ice cover as a result of a stress regime established within the plane of the ice. Tectonic uplift – The portion of the total geologic uplift of the mean earth surface, not attributable to an isostatic response to unloading Mountain range – A geographic area containing several geologically related mountains Mountain chain Hill chain Norsk Geologisk Tidsskrift, Volume 69 Universitetsforlaget, 1989 page 40 https://books.google.com/books?id=dXK7AAAAIAAJ Physical Geography: Introduction To Earth page 164 https://books.google.com/books?id=dC7qhGQpBYkC
Snowdonia is a mountainous region in northwestern Wales and a national park of 823 square miles in area. It was the first to be designated of the three national parks in Wales, in 1951, it contains the highest peaks in the United Kingdom outside of Scotland. The English name for the area derives from Snowdon, the highest mountain in Wales at 3560 ft. In Welsh, the area is named Eryri. A held belief is that the name is derived from eryr, thus means'the abode/land of eagles', but recent evidence is that it means Highlands, is related to the Latin oriri as leading Welsh scholar Sir Ifor Williams proved; the term Eryri first appeared in a manuscript in the 9th-century Historia Brittonum, in an account of the downfall of the semi-legendary 5th-century king Gwrtheyrn. In the Middle Ages the title Prince of Wales and Lord of Snowdonia was used by Llywelyn ap Gruffudd. Before the boundaries of the national park were designated, "Snowdonia" was used to refer to a smaller area, namely the upland area of northern Gwynedd centred on the Snowdon massif, whereas the national park covers an area more than twice that size extending far to the south into Meirionnydd.
This is apparent in books published prior to 1951, such as the classic travelogue Wild Wales by George Borrow and The Mountains of Snowdonia by H. Carr & G. Lister. F. J. North, as editor of the book Snowdonia, states "When the Committee delineated provisional boundaries, they included areas some distance beyond Snowdonia proper." The traditional Snowdonia thus includes the ranges of Snowdon and its satellites, the Glyderau, the Carneddau and the Moel Siabod group. It does not include the hills to the south of Maentwrog; as Eryri, this area has a unique place in Welsh history and culture. Snowdonia National Park was established in 1951 as the third national park in Britain, following the Peak District and the Lake District, it covers 827 square miles, has 37 miles of coastline. The Snowdonia National Park covers parts of the counties of Conwy; the park is governed by the Snowdonia National Park Authority, made up of local government and Welsh representatives, its main offices are at Penrhyndeudraeth.
Unlike national parks in other countries, Snowdonia are made up of both public and private lands under central planning authority. The makeup of land ownership at Snowdonia is as follows: More than 26,000 people live within the park. 58.6% of the population could speak Welsh in 2011. While most of the land is either open or mountainous land, there is a significant amount of agricultural activity within the park. Since the local government re-organisation of 1998, the park lies in the county of Gwynedd, in the county borough of Conwy, it is governed by the 18-member Snowdonia National Park Authority. Unusually, Snowdonia National Park has a hole in the middle, around the town of Blaenau Ffestiniog, a slate quarrying centre; this was deliberately excluded from the park when it was set up to allow the development of new light industry to replace the reduced slate industry. The Snowdonia Society is a registered charity formed in 1967, it is a voluntary group of people with an interest in its protection.
Amory Lovins led the successful 1970s opposition to stop Rio Tinto digging up the area for a massive mine. Research indicates that there were 3.67 million visitors to Snowdonia National Park in 2013, with 9.74 million tourist days spent in the park during that year. Total tourist expenditure was £433.6 million in 2013. Snowdonia may be divided into four areas: The northernmost area is the most popular with tourists, includes Moel Hebog, Mynydd Mawr and the Nantlle Ridge; these last three groups are the highest mountains in Wales, include all Wales' mountains higher than 3000 feet. The second area includes peaks such as Moel Siabod, the Moelwynion, the mountains around Blaenau Ffestiniog; the third area includes the Rhinogydd in the west as well as the Arenig and the Migneint, Rhobell Fawr. This area is not as popular with tourists as the other areas, due to its remoteness; the southernmost area includes Cadair Idris, the Tarren range, the Dyfi hills, the Aran group, including Aran Fawddwy, the highest mountain in the United Kingdom south of Snowdon.
The Berwyn range to the south east, has the western part of it in the park, but the highest summits to the east have been omitted. Many of the hikers in the area concentrate on Snowdon itself, it is regarded as a fine mountain, but at times gets crowded. The other high mountains with their boulder-strewn summits—as well as Tryfan, one of the few mountains in the UK south of Scotland whose ascent needs hands as well as feet—are very popular. However, there are some spectacular walks in Snowdonia on the lower mountains, they tend to be unfrequented. Among hikers' favourites are Y Garn along the ridge to Elidir Fawr.
Allt-fawr is a mountain in Snowdonia, North Wales and forms part of the Moelwynion group. It is on the internal border of Snowdonia National Park, overlooks the town of Blaenau Ffestiniog, with its numerous slate quarries, as well as the Tanygrisiau reservoir and power station. On the northern slope of Allt-fawr is the Oakeley Quarry, the world's largest underground slate mine. On the southern slope is the large Cwmorthin Quarry; these two mines are joined underneath the summit of Allt-fawr and the extensive chambering and adits are visible on the surface of the mountain where underground workings have collapsed. Www.geograph.co.uk: photos of Allt-fawr and surrounding area
A mountain range or hill range is a series of mountains or hills ranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form and alignment that have arisen from the same cause an orogeny. Mountain ranges are formed by a variety of geological processes, but most of the significant ones on Earth are the result of plate tectonics. Mountain ranges are found on many planetary mass objects in the Solar System and are a feature of most terrestrial planets. Mountain ranges are segmented by highlands or mountain passes and valleys. Individual mountains within the same mountain range do not have the same geologic structure or petrology, they may be a mix of different orogenic expressions and terranes, for example thrust sheets, uplifted blocks, fold mountains, volcanic landforms resulting in a variety of rock types. Most geologically young mountain ranges on the Earth's land surface are associated with either the Pacific Ring of Fire or the Alpide Belt.
The Pacific Ring of Fire includes the Andes of South America, extends through the North American Cordillera along the Pacific Coast, the Aleutian Range, on through Kamchatka, Taiwan, the Philippines, Papua New Guinea, to New Zealand. The Andes is 7,000 kilometres long and is considered the world's longest mountain system; the Alpide belt includes Indonesia and Southeast Asia, through the Himalaya, Caucasus Mountains, Balkan Mountains fold mountain range, the Alps, ends in the Spanish mountains and the Atlas Mountains. The belt includes other European and Asian mountain ranges; the Himalayas contain the highest mountains in the world, including Mount Everest, 8,848 metres high and traverses the border between China and Nepal. Mountain ranges outside these two systems include the Arctic Cordillera, the Urals, the Appalachians, the Scandinavian Mountains, the Great Dividing Range, the Altai Mountains and the Hijaz Mountains. If the definition of a mountain range is stretched to include underwater mountains the Ocean Ridges form the longest continuous mountain system on Earth, with a length of 65,000 kilometres.
The mountain systems of the earth are characterized by a tree structure, where mountain ranges can contain sub-ranges. The sub-range relationship is expressed as a parent-child relationship. For example, the White Mountains of New Hampshire and the Blue Ridge Mountains are sub-ranges of the Appalachian Mountains. Equivalently, the Appalachians are the parent of the White Mountains and Blue Ridge Mountains, the White Mountains and the Blue Ridge Mountains are children of the Appalachians; the parent-child expression extends to the sub-ranges themselves: the Sandwich Range and the Presidential Range are children of the White Mountains, while the Presidential Range is parent to the Northern Presidential Range and Southern Presidential Range. The position of mountains influences climate, such as snow; when air masses move up and over mountains, the air cools producing orographic precipitation. As the air descends on the leeward side, it warms again and is drier, having been stripped of much of its moisture.
A rain shadow will affect the leeward side of a range. Mountain ranges are subjected to erosional forces which work to tear them down; the basins adjacent to an eroding mountain range are filled with sediments which are buried and turned into sedimentary rock. Erosion is at work while the mountains are being uplifted until the mountains are reduced to low hills and plains; the early Cenozoic uplift of the Rocky Mountains of Colorado provides an example. As the uplift was occurring some 10,000 feet of Mesozoic sedimentary strata were removed by erosion over the core of the mountain range and spread as sand and clays across the Great Plains to the east; this mass of rock was removed as the range was undergoing uplift. The removal of such a mass from the core of the range most caused further uplift as the region adjusted isostatically in response to the removed weight. Rivers are traditionally believed to be the principal cause of mountain range erosion, by cutting into bedrock and transporting sediment.
Computer simulation has shown that as mountain belts change from tectonically active to inactive, the rate of erosion drops because there are fewer abrasive particles in the water and fewer landslides. Mountains on other planets and natural satellites of the Solar System are isolated and formed by processes such as impacts, though there are examples of mountain ranges somewhat similar to those on Earth. Saturn's moon Titan and Pluto, in particular exhibit large mountain ranges in chains composed of ices rather than rock. Examples include the Mithrim Montes and Doom Mons on Titan, Tenzing Montes and Hillary Montes on Pluto; some terrestrial planets other than Earth exhibit rocky mountain ranges, such as Maxwell Montes on Venus taller than any on Earth and Tartarus Montes on Mars, Jupiter's moon Io has mountain ranges formed from tectonic processes including Boösaule Montes, Dorian Montes, Hi'iaka Montes and Euboea Montes. Peakbagger Ranges Home Page Bivouac.com