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108-559: Sediments are most often transported by water ( fluvial processes ), but also wind ( aeolian processes ) and glaciers . Beach sands and river channel deposits are examples of fluvial transport and deposition , though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice-transported sediments. Sediment can be classified based on its grain size , grain shape, and composition. Sediment size

216-468: A "bitter river" ( Oceanus ), with seven islands arranged around it so as to form a seven-pointed star. The accompanying text mentions seven outer regions beyond the encircling ocean. The descriptions of five of them have survived. In contrast to the Imago Mundi , an earlier Babylonian world map dating back to the 9th century BC depicted Babylon as being further north from the center of the world, though it

324-402: A consequence of accessibility ." Geography is a branch of inquiry that focuses on spatial information on Earth. It is an extremely broad topic and can be broken down multiple ways. There have been several approaches to doing this spanning at least several centuries, including "four traditions of geography" and into distinct branches. The Four traditions of geography are often used to divide

432-644: A country have become erodible. For example, on the Madagascar high central plateau , which constitutes approximately ten percent of that country's land area, most of the land area is devegetated, and gullies have eroded into the underlying soil to form distinctive gulleys called lavakas . These are typically 40 meters (130 ft) wide, 80 meters (260 ft) long and 15 meters (49 ft) deep. Some areas have as many as 150 lavakas/square kilometer, and lavakas may account for 84% of all sediments carried off by rivers. This siltation results in discoloration of rivers to

540-463: A dark red brown color and leads to fish kills. In addition, sedimentation of river basins implies sediment management and siltation costs.The cost of removing an estimated 135 million m of accumulated sediments due to water erosion only is likely exceeding 2.3 billion euro (€) annually in the EU and UK, with large regional differences between countries. Erosion is also an issue in areas of modern farming, where

648-526: A focus on space, place, time, and scale. Today, geography is an extremely broad discipline with multiple approaches and modalities. There have been multiple attempts to organize the discipline, including the four traditions of geography, and into branches. Techniques employed can generally be broken down into quantitative and qualitative approaches, with many studies taking mixed-methods approaches. Common techniques include cartography , remote sensing , interviews , and surveying . Geography

756-418: A geographic information system). Remote sensing aids in land use, land cover (LULC) mapping, by helping to determine both what is naturally occurring on a piece of land and what human activities are taking place on it. Geostatistics deal with quantitative data analysis, specifically the application of a statistical methodology to the exploration of geographic phenomena. Geostatistics is used extensively in

864-432: A grain, such as pits, fractures, ridges, and scratches. These are most commonly evaluated on quartz grains, because these retain their surface markings for long periods of time. Surface texture varies from polished to frosted, and can reveal the history of transport of the grain; for example, frosted grains are particularly characteristic of aeolian sediments, transported by wind. Evaluation of these features often requires

972-606: A high level of information for Ptolemy to construct detailed atlases . He extended the work of Hipparchus , using a grid system on his maps and adopting a length of 56.5 miles for a degree. From the 3rd century onwards, Chinese methods of geographical study and writing of geographical literature became much more comprehensive than what was found in Europe at the time (until the 13th century). Chinese geographers such as Liu An , Pei Xiu , Jia Dan , Shen Kuo , Fan Chengda , Zhou Daguan , and Xu Xiake wrote important treatises, yet by

1080-458: A higher density and viscosity . In typical rivers the largest carried sediment is of sand and gravel size, but larger floods can carry cobbles and even boulders . Wind results in the transportation of fine sediment and the formation of sand dune fields and soils from airborne dust. Glaciers carry a wide range of sediment sizes, and deposit it in moraines . The overall balance between sediment in transport and sediment being deposited on

1188-493: A history, they also exist in space and have a geography. For something to exist in the realm of geography, it must be able to be described spatially. Thus, space is the most fundamental concept at the foundation of geography. The concept is so basic, that geographers often have difficulty defining exactly what it is. Absolute space is the exact site, or spatial coordinates, of objects, persons, places, or phenomena under investigation. We exist in space. Absolute space leads to

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1296-426: A hydrodynamic sorting process within the marine environment leading to a seaward fining of sediment grain size. One cause of high sediment loads is slash and burn and shifting cultivation of tropical forests. When the ground surface is stripped of vegetation and then seared of all living organisms, the upper soils are vulnerable to both wind and water erosion. In a number of regions of the earth, entire sectors of

1404-565: A product with greater information than a two-dimensional image of places, names, and topography. This approach offers more inclusive strategies than more traditional cartographic approaches for connecting the complex layers that makeup places. Ethnographical research techniques are used by human geographers. In cultural geography , there is a tradition of employing qualitative research techniques, also used in anthropology and sociology. Participant observation and in-depth interviews provide human geographers with qualitative data. Geopoetics

1512-470: A result, can cause exposed sediment to become more susceptible to erosion and delivery to the marine environment during rainfall events. Sediment can negatively affect corals in many ways, such as by physically smothering them, abrading their surfaces, causing corals to expend energy during sediment removal, and causing algal blooms that can ultimately lead to less space on the seafloor where juvenile corals (polyps) can settle. When sediments are introduced into

1620-454: A short distance then settling again). If the upwards velocity is higher than the settling velocity, the sediment will be transported high in the flow as wash load . As there are generally a range of different particle sizes in the flow, it is common for material of different sizes to move through all areas of the flow for given stream conditions. Sediment motion can create self-organized structures such as ripples , dunes , or antidunes on

1728-470: A single person from a single location. The European Age of Discovery during the 16th and the 17th centuries, where many new lands were discovered and accounts by European explorers such as Christopher Columbus , Marco Polo , and James Cook revived a desire for both accurate geographic detail and more solid theoretical foundations in Europe. In 1650, the first edition of the Geographia Generalis

1836-434: A structured or semi-structured approach during interviews involving specific questions or discussion points when utilized for research purposes. These questions are designed to extract focused information about the research topic while being flexible enough to allow participants to express their experiences and viewpoints, such as through open-ended questions. The concept of geography is present in all cultures, and therefore

1944-439: A system. The amount of time an individual, or group of people, spends in a place will often shape their attachment and perspective to that place. Time constrains the possible paths that can be taken through space, given a starting point, possible routes, and rate of travel. Visualizing time over space is challenging in terms of cartography, and includes Space-Prism, advanced 3D geovisualizations, and animated maps . Scale in

2052-417: A variety of fields, including hydrology , geology, petroleum exploration, weather analysis, urban planning , logistics, and epidemiology . The mathematical basis for geostatistics derives from cluster analysis , linear discriminant analysis and non-parametric statistical tests , and a variety of other subjects. Applications of geostatistics rely heavily on geographic information systems , particularly for

2160-606: Is a systematic study of the Earth (other celestial bodies are specified, such as "geography of Mars", or given another name, such as areography in the case of Mars), its features, and phenomena that take place on it. For something to fall into the domain of geography, it generally needs some sort of spatial component that can be placed on a map , such as coordinates , place names, or addresses . This has led to geography being associated with cartography and place names. Although many geographers are trained in toponymy and cartology, this

2268-750: Is an interdisciplinary approach that combines geography and poetry to explore the interconnectedness between humans, space, place, and the environment. Geopoetics is employed as a mixed methods tool to explain the implications of geographic research. It is often employed to address and communicate the implications of complex topics, such as the anthropocene . Geographers employ interviews to gather data and acquire valuable understandings from individuals or groups regarding their encounters, outlooks, and opinions concerning spatial phenomena. Interviews can be carried out through various mediums, including face-to-face interactions, phone conversations, online platforms, or written exchanges. Geographers typically adopt

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2376-436: Is an ongoing source of debate in geography and is unlikely to be resolved anytime soon. Several laws have been proposed, and Tobler's first law of geography is the most generally accepted in geography. Some have argued that geographic laws do not need to be numbered. The existence of a first invites a second, and many have proposed themselves as that. It has also been proposed that Tobler's first law of geography should be moved to

2484-414: Is concerned with the study of processes and patterns in the natural environment like the atmosphere , hydrosphere , biosphere , and geosphere . Technical geography is interested in studying and applying techniques and methods to store, process, analyze, visualize, and use spatial data. It is the newest of the branches, the most controversial, and often other terms are used in the literature to describe

2592-475: Is credited to Hipparchus . He employed a sexagesimal system that was derived from Babylonian mathematics . The meridians were subdivided into 360°, with each degree further subdivided into 60 ( minutes ). To measure the longitude at different locations on Earth, he suggested using eclipses to determine the relative difference in time. The extensive mapping by the Romans as they explored new lands would later provide

2700-666: Is enormous. It has been estimated that the Mississippi River annually carries 406 million tons of sediment to the sea, the Yellow River 796 million tons, and the Po River in Italy 67 million tons. The names of many rivers derive from the color that the transported matter gives the water. For example, the Yellow River (Huang He) in China is named after the hue of the sediment it carries, and

2808-538: Is expected to be delivered to the outlet of the river. The sediment transfer and deposition can be modelled with sediment distribution models such as WaTEM/SEDEM. In Europe, according to WaTEM/SEDEM model estimates the Sediment Delivery Ratio is about 15%. Watershed development near coral reefs is a primary cause of sediment-related coral stress. The stripping of natural vegetation in the watershed for development exposes soil to increased wind and rainfall and, as

2916-469: Is impacted by all other locations on Earth. In one of Yi-Fu Tuan 's papers, he explains that in his view, geography is the study of Earth as a home for humanity, and thus place and the complex meaning behind the term is central to the discipline of geography. Time is usually thought to be within the domain of history , however, it is of significant concern in the discipline of geography. In physics, space and time are not separated, and are combined into

3024-581: Is measured on a log base 2 scale, called the "Phi" scale, which classifies particles by size from "colloid" to "boulder". The shape of particles can be defined in terms of three parameters. The form is the overall shape of the particle, with common descriptions being spherical, platy, or rodlike. The roundness is a measure of how sharp grain corners are. This varies from well-rounded grains with smooth corners and edges to poorly rounded grains with sharp corners and edges. Finally, surface texture describes small-scale features such as scratches, pits, or ridges on

3132-417: Is not certain what that center was supposed to represent. The ideas of Anaximander (c. 610–545 BC): considered by later Greek writers to be the true founder of geography, come to us through fragments quoted by his successors. Anaximander is credited with the invention of the gnomon , the simple, yet efficient Greek instrument that allowed the early measurement of latitude . Thales is also credited with

3240-438: Is not their main preoccupation. Geographers study the Earth's spatial and temporal distribution of phenomena, processes, and features as well as the interaction of humans and their environment . Because space and place affect a variety of topics, such as economics, health, climate , plants, and animals, geography is highly interdisciplinary. The interdisciplinary nature of the geographical approach depends on an attentiveness to

3348-526: Is one of the broadest, is consistent with the naming convention of the other two branches, has been in use since the 1700s, and has been used by the UNESCO Encyclopedia of Life Support Systems to divide geography into themes. As academic fields increasingly specialize in their nature, technical geography has emerged as a branch of geography specializing in geographic methods and thought. The emergence of technical geography has brought new relevance to

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3456-454: Is related to everything else, but near things are more related than distant things." As spatial interrelationships are key to this synoptic science, maps are a key tool. Classical cartography has been joined by a more modern approach to geographical analysis, computer-based geographic information systems (GIS). In their study, geographers use four interrelated approaches: Quantitative methods in geography became particularly influential in

3564-430: Is spherical in shape, with the credit going either to Parmenides or Pythagoras . Anaxagoras was able to demonstrate that the profile of the Earth was circular by explaining eclipses . However, he still believed that the Earth was a flat disk, as did many of his contemporaries. One of the first estimates of the radius of the Earth was made by Eratosthenes . The first rigorous system of latitude and longitude lines

3672-536: Is the study of earth's seasons, climate , atmosphere , soil , streams, landforms, and oceans. Physical geographers will often work in identifying and monitoring the use of natural resources. Human geography (or anthropogeography) is a branch of geography that focuses on studying patterns and processes that shape human society. It encompasses the human, political, cultural , social, and economic aspects. In industry, human geographers often work in city planning, public health, or business analysis. Various approaches to

3780-542: Is the study of the lands, features, inhabitants, and phenomena of Earth . Geography is an all-encompassing discipline that seeks an understanding of Earth and its human and natural complexities —not merely where objects are, but also how they have changed and come to be. While geography is specific to Earth, many concepts can be applied more broadly to other celestial bodies in the field of planetary science . Geography has been called "a bridge between natural science and social science disciplines." Origins of many of

3888-411: Is transported as either bedload (the coarser fragments which move close to the bed) or suspended load (finer fragments carried in the water). There is also a component carried as dissolved material. For each grain size there is a specific flow velocity at which the grains start to move, called entrainment velocity . However the grains will continue to be transported even if the velocity falls below

3996-562: The Earth radius was only 16.8 km less than the modern value of 6,356.7 km. In contrast to his predecessors, who measured the Earth's circumference by sighting the Sun simultaneously from two different locations, al-Biruni developed a new method of using trigonometric calculations based on the angle between a plain and mountain top, which yielded more accurate measurements of the Earth's circumference, and made it possible for it to be measured by

4104-514: The National Council for Geographic Education and the Association of American Geographers in 1984. These themes are Location, place, relationships within places (often summarized as Human-Environment Interaction), movement, and regions. The five themes of geography have shaped how American education approaches the topic in the years since. Just as all phenomena exist in time and thus have

4212-604: The Royal Danish Geographical Society in 1876 and the National Geographic Society in 1888. The influence of Immanuel Kant , Alexander von Humboldt , Carl Ritter , and Paul Vidal de la Blache can be seen as a major turning point in geography from philosophy to an academic subject. Geographers such as Richard Hartshorne and Joseph Kerski have regarded both Humboldt and Ritter as the founders of modern geography, as Humboldt and Ritter were

4320-638: The Spatial or Locational Tradition, the Man-Land or Human-Environment Interaction Tradition (sometimes referred to as Integrated geography ), the Area Studies or Regional Tradition, and the Earth Science Tradition. These concepts are broad sets of geography philosophies bound together within the discipline. They are one of many ways geographers organize the major sets of thoughts and philosophies within

4428-463: The White Nile is named for the clay it carries. The main kinds of fluvial processes are: The major fluvial (river and stream) depositional environments include: Rivers and streams carry sediment in their flows. This sediment can be in a variety of locations within the flow, depending on the balance between the upwards velocity on the particle (drag and lift forces), and the settling velocity of

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4536-472: The built environment and how humans create, view, manage, and influence space. Physical geography examines the natural environment and how organisms , climate, soil , water, and landforms produce and interact. The difference between these approaches led to the development of integrated geography , which combines physical and human geography and concerns the interactions between the environment and humans. Technical geography involves studying and developing

4644-470: The first law of geography , "everything is related to everything else, but near things are more related than distant things." This law summarizes the first assumption geographers make about the world. The discipline of geography, especially physical geography, and geology have significant overlap. In the past, the two have often shared academic departments at universities, a point that has led to conflict over resources. Both disciplines do seek to understand

4752-607: The interpolation (estimate) of unmeasured points. Geographers are making notable contributions to the method of quantitative techniques. Qualitative methods in geography are descriptive rather than numerical or statistical in nature. They add context to concepts, and explore human concepts like beliefs and perspective that are difficult or impossible to quantify. Human geography is much more likely to employ qualitative methods than physical geography. Increasingly, technical geographers are attempting to employ GIS methods to qualitative datasets. Qualitative cartography employs many of

4860-452: The lithosphere , atmosphere , hydrosphere , and biosphere . Places do not exist in a vacuum and instead have complex spatial relationships with each other, and place is concerned how a location is situated in relation to all other locations. As a discipline then, the term place in geography includes all spatial phenomena occurring at a location, the diverse uses and meanings humans ascribe to that location, and how that location impacts and

4968-506: The quantitative revolution , and critical geography . The strong interdisciplinary links between geography and the sciences of geology and botany , as well as economics, sociology, and demographics , have also grown greatly, especially as a result of earth system science that seeks to understand the world in a holistic view. New concepts and philosophies have emerged from the rapid advancement of computers, quantitative methods, and interdisciplinary approaches. In 1970, Waldo Tobler proposed

5076-546: The rocks on the Earth's surface and the processes that change them over time. Geology employs many of the tools and techniques of technical geographers, such as GIS and remote sensing to aid in geological mapping . However, geology includes research that goes beyond the spatial component, such as the chemical analysis of rocks and biogeochemistry . The discipline of History has significant overlap with geography, especially human geography. Like geology, history and geography have shared university departments. Geography provides

5184-564: The seafloor in the South Pacific Gyre (SPG) ("the deadest spot in the ocean"), and could be the longest-living life forms ever found. Fluvial In geography and geology , fluvial sediment processes or fluvial sediment transport are associated with rivers and streams and the deposits and landforms created by sediments . It can result in the formation of ripples and dunes , in fractal -shaped patterns of erosion, in complex patterns of natural river systems, and in

5292-456: The "Balkhī school" of terrestrial mapping in Baghdad . Suhrāb, a late tenth century Muslim geographer accompanied a book of geographical coordinates, with instructions for making a rectangular world map with equirectangular projection or cylindrical equidistant projection. Abu Rayhan Biruni (976–1048) first described a polar equi- azimuthal equidistant projection of the celestial sphere . He

5400-695: The 17th century advanced ideas and methods of Western-style geography were adopted in China. During the Middle Ages , the fall of the Roman empire led to a shift in the evolution of geography from Europe to the Islamic world . Muslim geographers such as Muhammad al-Idrisi produced detailed world maps (such as Tabula Rogeriana ), while other geographers such as Yaqut al-Hamawi , Abu Rayhan Biruni , Ibn Battuta , and Ibn Khaldun provided detailed accounts of their journeys and

5508-470: The Earth for automatic retrieval by a computer in an accurate manner appropriate to the information's purpose. In addition to all of the other subdisciplines of geography, GIS specialists must understand computer science and database systems. GIS has revolutionized the field of cartography: nearly all mapmaking is now done with the assistance of some form of GIS software . The science of using GIS software and GIS techniques to represent, analyse, and predict

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5616-493: The Earth most effectively and behavioural psychology to induce the readers of their maps to act on the information. They must learn geodesy and fairly advanced mathematics to understand how the shape of the Earth affects the distortion of map symbols projected onto a flat surface for viewing. It can be said, without much controversy, that cartography is the seed from which the larger field of geography grew. Geographic information systems (GIS) deal with storing information about

5724-529: The Earth's land surface , ocean, and atmosphere, because it: (a) supplies objective information at a variety of spatial scales (local to global), (b) provides a synoptic view of the area of interest, (c) allows access to distant and inaccessible sites, (d) provides spectral information outside the visible portion of the electromagnetic spectrum , and (e) facilitates studies of how features/areas change over time. Remotely sensed data may be analyzed independently or in conjunction with other digital data layers (e.g., in

5832-424: The Earth's surface, the activity and use that occurs, has occurred, and will occur at the coordinates, and the meaning ascribed to the space by human individuals and groups. This can be extraordinarily complex, as different spaces may have different uses at different times and mean different things to different people. In physical geography, a place includes all of the physical phenomena that occur in space, including

5940-507: The art, science, and technology of making maps. Cartographers study the Earth's surface representation with abstract symbols (map making). Although other subdisciplines of geography rely on maps for presenting their analyses, the actual making of maps is abstract enough to be regarded separately. Cartography has grown from a collection of drafting techniques into an actual science. Cartographers must learn cognitive psychology and ergonomics to understand which symbols convey information about

6048-407: The bed is composed of loose sediment which can be mobilized by such stresses, then the bed will be lowered purely by clearwater flow. In addition, if the river carries significant quantities of sediment , this material can act as tools to enhance wear of the bed ( abrasion ). At the same time the fragments themselves are ground down, becoming smaller and more rounded ( attrition ). Sediment in rivers

6156-596: The bed is given by the Exner equation . This expression states that the rate of increase in bed elevation due to deposition is proportional to the amount of sediment that falls out of the flow. This equation is important in that changes in the power of the flow change the ability of the flow to carry sediment, and this is reflected in the patterns of erosion and deposition observed throughout a stream. This can be localized, and simply due to small obstacles; examples are scour holes behind boulders, where flow accelerates, and deposition on

6264-579: The body of water. Terrigenous material is often supplied by nearby rivers and streams or reworked marine sediment (e.g. sand ). In the mid-ocean, the exoskeletons of dead organisms are primarily responsible for sediment accumulation. Deposited sediments are the source of sedimentary rocks , which can contain fossils of the inhabitants of the body of water that were, upon death, covered by accumulating sediment. Lake bed sediments that have not solidified into rock can be used to determine past climatic conditions. The major areas for deposition of sediments in

6372-454: The book expanded on these key concepts by adding "Environmental systems," "Social Systems," "Nature," " Globalization ," "Development," and "Risk," demonstrating how challenging narrowing the field can be. Another approach used extensively in teaching geography are the Five themes of geography established by "Guidelines for Geographic Education: Elementary and Secondary Schools," published jointly by

6480-406: The broad discipline of geography by serving as a set of unique methods for managing the interdisciplinary nature of the phenomena under investigation. While human and physical geographers use the techniques employed by technical geographers, technical geography is more concerned with the fundamental spatial concepts and technologies than the nature of the data. It is therefore closely associated with

6588-417: The coastal regions of the ocean, the proportion of land, marine, and organic-derived sediment that characterizes the seafloor near sources of sediment output is altered. In addition, because the source of sediment (i.e., land, ocean, or organically) is often correlated with how coarse or fine sediment grain sizes that characterize an area are on average, grain size distribution of sediment will shift according to

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6696-438: The concept of spacetime . Geography is subject to the laws of physics, and in studying things that occur in space, time must be considered. Time in geography is more than just the historical record of events that occurred at various discrete coordinates; but also includes modeling the dynamic movement of people, organisms, and things through space. Time facilitates movement through space, ultimately allowing things to flow through

6804-424: The concepts in geography can be traced to Greek Eratosthenes of Cyrene, who may have coined the term "geographia" ( c.  276 BC  – c.  195/194 BC ). The first recorded use of the word γεωγραφία was as the title of a book by Greek scholar Claudius Ptolemy (100 – 170 AD). This work created the so-called "Ptolemaic tradition" of geography, which included "Ptolemaic cartographic theory." However,

6912-468: The concepts of geography (such as cartography ) date back to the earliest attempts to understand the world spatially, with the earliest example of an attempted world map dating to the 9th century BCE in ancient Babylon . The history of geography as a discipline spans cultures and millennia, being independently developed by multiple groups, and cross-pollinated by trade between these groups. The core concepts of geography consistent between all approaches are

7020-405: The context of a map is the ratio between a distance measured on the map and the corresponding distance as measured on the ground. This concept is fundamental to the discipline of geography, not just cartography, in that phenomena being investigated appear different depending on the scale used. Scale is the frame that geographers use to measure space, and ultimately to understand a place. During

7128-419: The development of floodplains and the occurrence of flash floods . Sediment moved by water can be larger than sediment moved by air because water has both a higher density and viscosity . In typical rivers the largest carried sediment is of sand and gravel size, but larger floods can carry cobbles and even boulders . When the stream or rivers are associated with glaciers , ice sheets , or ice caps ,

7236-452: The different historical approach theories geographers have taken to the discipline. In contrast, geography's branches describe contemporary applied geographical approaches. Geography is an extremely broad field. Because of this, many view the various definitions of geography proposed over the decades as inadequate. To address this, William D. Pattison proposed the concept of the "Four traditions of Geography" in 1964. These traditions are

7344-399: The discipline during the quantitative revolution of the 1950s and 60s. These methods revitalized the discipline in many ways, allowing scientific testing of hypotheses and proposing scientific geographic theories and laws. The quantitative revolution heavily influenced and revitalized technical geography, and lead to the development of the subfield of quantitative geography. Cartography is

7452-514: The discipline into a section containing content such as cartographic techniques and globes. There are several other terms, often used interchangeably with technical geography to subdivide the discipline, including "techniques of geographic analysis," "Geographic Information Technology," "Geography method's and techniques," " Geographic Information Science ," " geoinformatics ," " geomatics ," and "information geography". There are subtle differences to each concept and term; however, technical geography

7560-512: The discipline of geography is normally concerned with the Earth, the term can also be informally used to describe the study of other worlds, such as the planets of the Solar System and even beyond. The study of systems larger than the Earth itself usually forms part of Astronomy or Cosmology . The study of other planets is usually called planetary science . Alternative terms such as areography (geography of Mars) have been employed to describe

7668-552: The discipline. In another approach to the abovementioned four traditions, geography is organized into applied branches. The UNESCO Encyclopedia of Life Support Systems organizes geography into the three categories of human geography , physical geography , and technical geography . Some publications limit the number of branches to physical and human, describing them as the principal branches. Geographers rarely focus on just one of these topics, often using one as their primary focus and then incorporating data and methods from

7776-421: The edges and corners of particle are. Complex mathematical formulas have been devised for its precise measurement, but these are difficult to apply, and most geologists estimate roundness from comparison charts. Common descriptive terms range from very angular to angular to subangular to subrounded to rounded to very rounded, with increasing degree of roundness. Surface texture describes the small-scale features of

7884-407: The emerging category. These branches use similar geographic philosophies, concepts, and tools and often overlap significantly. Physical geography (or physiography) focuses on geography as an Earth science . It aims to understand the physical problems and the issues of lithosphere , hydrosphere , atmosphere , pedosphere , and global flora and fauna patterns ( biosphere ). Physical geography

7992-470: The entrainment velocity due to the reduced (or removed) friction between the grains and the river bed. Eventually the velocity will fall low enough for the grains to be deposited. This is shown by the Hjulström curve . A river is continually picking up and dropping solid particles of rock and soil from its bed throughout its length. Where the river flow is fast, more particles are picked up than dropped. Where

8100-514: The first to establish geography as an independent scientific discipline. Over the past two centuries, the advancements in technology with computers have led to the development of geomatics and new practices such as participant observation and geostatistics being incorporated into geography's portfolio of tools. In the West during the 20th century, the discipline of geography went through four major phases: environmental determinism , regional geography ,

8208-510: The flow. In geography and geology , fluvial sediment processes or fluvial sediment transport are associated with rivers and streams and the deposits and landforms created by sediments. It can result in the formation of ripples and dunes , in fractal -shaped patterns of erosion, in complex patterns of natural river systems, and in the development of floodplains and the occurrence of flash floods . Sediment moved by water can be larger than sediment moved by air because water has both

8316-496: The geography of the regions they visited. Turkish geographer Mahmud al-Kashgari drew a world map on a linguistic basis, and later so did Piri Reis ( Piri Reis map ). Further, Islamic scholars translated and interpreted the earlier works of the Romans and the Greeks and established the House of Wisdom in Baghdad for this purpose. Abū Zayd al-Balkhī , originally from Balkh , founded

8424-449: The heights of mountains, depths of the valleys , and expanse of the horizon . He also discussed human geography and the planetary habitability of the Earth. He also calculated the latitude of Kath, Khwarezm , using the maximum altitude of the Sun, and solved a complex geodesic equation to accurately compute the Earth's circumference , which was close to modern values of the Earth's circumference. His estimate of 6,339.9 km for

8532-589: The history of the discipline is a series of competing narratives, with concepts emerging at various points across space and time. The oldest known world maps date back to ancient Babylon from the 9th century BC. The best known Babylonian world map, however, is the Imago Mundi of 600 BC. The map as reconstructed by Eckhard Unger shows Babylon on the Euphrates , surrounded by a circular landmass showing Assyria , Urartu , and several cities, in turn surrounded by

8640-539: The inside of meander bends. Erosion and deposition can also be regional; erosion can occur due to dam removal and base level fall. Deposition can occur due to dam emplacement that causes the river to pool and deposit its entire load, or due to base level rise. Seas, oceans, and lakes accumulate sediment over time. The sediment can consist of terrigenous material, which originates on land, but may be deposited in either terrestrial, marine, or lacustrine (lake) environments, or of sediments (often biological) originating in

8748-402: The laws of nature and to mark their influences upon man. This is 'a description of the world'—that is Geography. In a word, Geography is a Science—a thing not of mere names but of argument and reason, of cause and effect. Geography as a discipline can be split broadly into three main branches: human geography , physical geography , and technical geography . Human geography largely focuses on

8856-404: The long, intermediate, and short axis lengths of the particle. The form ψ l {\displaystyle \psi _{l}} varies from 1 for a perfectly spherical particle to very small values for a platelike or rodlike particle. An alternate measure was proposed by Sneed and Folk: which, again, varies from 0 to 1 with increasing sphericity. Roundness describes how sharp

8964-435: The marine environment include: One other depositional environment which is a mixture of fluvial and marine is the turbidite system, which is a major source of sediment to the deep sedimentary and abyssal basins as well as the deep oceanic trenches . Any depression in a marine environment where sediments accumulate over time is known as a sediment trap . The null point theory explains how sediment deposition undergoes

9072-414: The other branches. Often, geographers are asked to describe what they do by individuals outside the discipline and are likely to identify closely with a specific branch, or sub-branch when describing themselves to lay people. Human geography studies people and their communities, cultures, economies, and environmental interactions by studying their relations with and across space and place. Physical geography

9180-568: The particle. These relationships are shown in the following table for the Rouse number , which is a ratio of sediment settling velocity (fall velocity) to upwards velocity. Rouse = Settling velocity Upwards velocity from lift and drag = w s κ u ∗ {\displaystyle {\textbf {Rouse}}={\frac {\text{Settling velocity}}{\text{Upwards velocity from lift and drag}}}={\frac {w_{s}}{\kappa u_{*}}}} where If

9288-402: The prediction of eclipses. The foundations of geography can be traced to ancient cultures, such as the ancient, medieval, and early modern Chinese . The Greeks , who were the first to explore geography as both art and science, achieved this through Cartography , Philosophy , and Literature , or through Mathematics . There is some debate about who was the first person to assert that the Earth

9396-457: The quantitative revolution, geography shifted to an empirical law-making ( nomothetic ) approach. Several laws of geography have been proposed since then, most notably by Waldo Tobler and can be viewed as a product of the quantitative revolution. In general, some dispute the entire concept of laws in geography and the social sciences. These criticisms have been addressed by Tobler and others, such as Michael Frank Goodchild . However, this

9504-473: The relationship between physical and human phenomena and their spatial patterns. Names of places...are not geography...To know by heart a whole gazetteer full of them would not, in itself, constitute anyone a geographer. Geography has higher aims than this: it seeks to classify phenomena (alike of the natural and of the political world, in so far as it treats of the latter), to compare, to generalize, to ascend from effects to causes, and, in doing so, to trace out

9612-491: The relative input of land (typically fine), marine (typically coarse), and organically-derived (variable with age) sediment. These alterations in marine sediment characterize the amount of sediment suspended in the water column at any given time and sediment-related coral stress. In July 2020, marine biologists reported that aerobic microorganisms (mainly), in " quasi-suspended animation ", were found in organically-poor sediments, up to 101.5 million years old, 250 feet below

9720-471: The removal of native vegetation for the cultivation and harvesting of a single type of crop has left the soil unsupported. Many of these regions are near rivers and drainages. Loss of soil due to erosion removes useful farmland, adds to sediment loads, and can help transport anthropogenic fertilizers into the river system, which leads to eutrophication . The Sediment Delivery Ratio (SDR) is fraction of gross erosion (interill, rill, gully and stream erosion) that

9828-408: The river flow is slow, more particles are dropped than picked up. Areas where more particles are dropped are called alluvial or flood plains, and the dropped particles are called alluvium . Even small streams make alluvial deposits, but it is in floodplains and deltas of large rivers that large, geologically-significant alluvial deposits are found. The amount of matter carried by a large river

9936-516: The river or stream bed . These bedforms are often preserved in sedimentary rocks and can be used to estimate the direction and magnitude of the flow that deposited the sediment. Overland flow can erode soil particles and transport them downslope. The erosion associated with overland flow may occur through different methods depending on meteorological and flow conditions. Geography Geography (from Ancient Greek γεωγραφία geōgraphía ; combining gê 'Earth' and gráphō 'write')

10044-438: The same software and techniques as quantitative cartography. It may be employed to inform on map practices, or to visualize perspectives and ideas that are not strictly quantitative in nature. An example of a form of qualitative cartography is a Chorochromatic map of nominal data, such as land cover or dominant language group in an area. Another example is a deep map , or maps that combine geography and storytelling to produce

10152-533: The second and replaced with another. A few of the proposed laws of geography are below: Additionally, several variations or amendments to these laws exist within the literature, although not as well supported. For example, one paper proposed an amended version of Tobler's first law of geography, referred to in the text as the Tobler–von Thünen law , which states: "Everything is related to everything else, but near things are more related than distant things, as

10260-445: The spatial context within which historical events unfold. The physical geographic features of a region, such as its landforms, climate, and resources, shape human settlements, trade routes, and economic activities, which in turn influence the course of historical events. Thus, a historian must have a strong foundation in geography. Historians employ the techniques of technical geographers to create historical atlases and maps. While

10368-675: The spatial relationships is called geographic information science (GISc). Remote sensing is the art, science, and technology of obtaining information about Earth's features from measurements made at a distance. Remotely sensed data can be either passive, such as traditional photography , or active, such as LiDAR . A variety of platforms can be used for remote sensing, including satellite imagery , aerial photography (including consumer drones), and data obtained from hand-held sensors. Products from remote sensing include Digital elevation model and cartographic base maps. Geographers increasingly use remotely sensed data to obtain information about

10476-534: The spatial tradition of geography while being applied to the other two major branches. A technical geographer might work as a GIS analyst, a GIS developer working to make new software tools, or create general reference maps incorporating human and natural features. All geographic research and analysis start with asking the question "where," followed by "why there." Geographers start with the fundamental assumption set forth in Tobler's first law of geography , that "everything

10584-403: The study of human geography have also arisen through time and include: Technical geography concerns studying and developing tools, techniques, and statistical methods employed to collect, analyze, use, and understand spatial data. Technical geography is the most recently recognized, and controversial, of the branches. Its use dates back to 1749, when a book published by Edward Cave organized

10692-443: The surface of the grain. Form (also called sphericity ) is determined by measuring the size of the particle on its major axes. William C. Krumbein proposed formulas for converting these numbers to a single measure of form, such as where D L {\displaystyle D_{L}} , D I {\displaystyle D_{I}} , and D S {\displaystyle D_{S}} are

10800-407: The term glaciofluvial or fluvioglacial is used, as in periglacial flows and glacial lake outburst floods . Fluvial sediment processes include the motion of sediment and erosion or deposition on the river bed . The movement of water across the stream bed exerts a shear stress directly onto the bed. If the cohesive strength of the substrate is lower than the shear exerted, or

10908-557: The times when geography became recognized as a discrete academic discipline , and became part of a typical university curriculum in Europe (especially Paris and Berlin ). The development of many geographic societies also occurred during the 19th century, with the foundations of the Société de Géographie in 1821, the Royal Geographical Society in 1830, Russian Geographical Society in 1845, American Geographical Society in 1851,

11016-489: The tools and techniques used by geographers, such as remote sensing, cartography, and geographic information system. Narrowing down geography to a few key concepts is extremely challenging, and subject to tremendous debate within the discipline. In one attempt, the 1st edition of the book "Key Concepts in Geography" broke down this into chapters focusing on "Space," "Place," "Time," "Scale," and "Landscape." The 2nd edition of

11124-404: The upwards velocity is approximately equal to the settling velocity, sediment will be transported downstream entirely as suspended load . If the upwards velocity is much less than the settling velocity, but still high enough for the sediment to move (see Initiation of motion ), it will move along the bed as bed load by rolling, sliding, and saltating (jumping up into the flow, being transported

11232-493: The use of a scanning electron microscope . Composition of sediment can be measured in terms of: This leads to an ambiguity in which clay can be used as both a size-range and a composition (see clay minerals ). Sediment is transported based on the strength of the flow that carries it and its own size, volume, density, and shape. Stronger flows will increase the lift and drag on the particle, causing it to rise, while larger or denser particles will be more likely to fall through

11340-401: The view of the world as a photograph, with everything frozen in place when the coordinates were recorded. Today, geographers are trained to recognize the world as a dynamic space where all processes interact and take place, rather than a static image on a map. Place is one of the most complex and important terms in geography. In human geography, place is the synthesis of the coordinates on

11448-597: Was finding the latitude and longitude of a geographic location. While the problem of latitude was solved long ago, but that of longitude remained; agreeing on what zero meridians should be was only part of the problem. It was left to John Harrison to solve it by inventing the chronometer H-4 in 1760, and later in 1884 for the International Meridian Conference to adopt by convention the Greenwich meridian as zero meridians. The 18th and 19th centuries were

11556-551: Was published by Bernhardus Varenius , which was later edited and republished by others including Isaac Newton . This textbook sought to integrate new scientific discoveries and principles into classical geography and approach the discipline like the other sciences emerging, and is seen by some as the division between ancient and modern geography in the West. The Geographia Generalis contained both theoretical background and practical applications related to ship navigation. The remaining problem facing both explorers and geographers

11664-513: Was regarded as the most skilled when it came to mapping cities and measuring the distances between them, which he did for many cities in the Middle East and the Indian subcontinent . He often combined astronomical readings and mathematical equations to develop methods of pin-pointing locations by recording degrees of latitude and longitude . He also developed similar techniques when it came to measuring

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