Sunday, 7 July 2013

D - list of geographical terms and definitions

Dairy Farm: one which specialises in dairy cows, producing milk, butter, cheeses, yoghurt etc.
Dam: In geography terminology, a dam is an obstruction in the course of water, to raise the level of water.
Date Line: An imaginary line pointing north-south approximating to Meridian 180° (east to west) where the date changes by one day the Foment it is crossed.
Death Rate: As a part of geography terms list, death rate means the ratio of deaths to the total population in a given area and in a given time. It is generally measured in deaths per 1,000 persons of the total population in a given year.
Death rate: the number of deaths per 1000 people per year.
Death Rate: The number of people dying per 1,000 of the population.
Debris: Debris is defined as the rubble that is left behind after destruction and damage.
Decentralisation: the movement of shops, offices and industry away from urban centres in MEDCs and NICs into retail and business parks in the suburbs. Recent trends have been to decentralise still further out into many semi-rural locations. High land and labour costs are two of the main push factors.
Deciduous forest: Forests in which the trees lose their leaves each year.
Deciduous Woodland: Forest which comprises deciduous trees, characterized by flat and broad leaves which shed during fall are known as deciduous woodlands.
Declination: Declination is the point when the sun is at exact 90˚ above the horizon on a latitude.
Declining Region: one where traditional heavy industries are closing down leading to high unemployment and out-migration e.g. South Wales. See Deindustrialisation and Cycle of Decline.
Decomposer: Decomposer is an organism which decomposes the organic matter into its 'inorganic chemical compounds' for recycling through an ecosystem.
Decomposition: The process of conversion of organic matter into simpler substances by decomposers is called decomposition.
Deep Sea Trench: A deep, long and narrow depression in the sea floor is known as a deep sea trench. Mariana Trench in the Pacific ocean is known to be the deepest trench in the oceanic world. A trench has steep sides which go on for several kilometers.
Defensive Site: a settlement which usually grew at or around a fort or castle on top of a hill, although river meander bends, bridges, dry-point sites and coastal sites with cliffs were also good for defence.
Defensive Site: A place where a settlement can be easily defended against attack such as on a hilltop or surrounded by water.
Deforestation: Wanton cutting down of trees and clearing of forests for human use is called deforestation. Deforestation leads to soil erosion and reduces the capacity of the soil to retain water.
Deglaciation: Deglaciation means reduction of glacial cover due to rise in ablation than accumulation.
Deglomeration: Deglomeration is a movement of industrial unit such as factories and manufacturing units from densely populated areas.
Degradation: It is defined as the gradual wearing down of banks, rocks etc, which is caused by water and frost.
Degree: A unit of angular measure: A circle is divided into 360 degrees, represented by the º symbol. Degrees are used to divide the roughly spherical shape of the Earth for geographic and cartographic purposes.
Deindustrialisation: the decline of a country's traditional manufacturing industry due to exhaustion of raw materials, loss of markets and competition from NICs.
Delta: A flat area of deposited river silt found at the mouth of a river.
Delta: A triangular piece of land at the mouth of river.
Delta: an area of flat, very fertile land at the mouth of a river which extends out into the sea. Deltas are formed from mud and silt brought down by rivers.
Delta: In geographical terminology, a delta is a triangular plain, usually at the mouth of the river, where alluvial soil is deposited.
Delta: a river mouth choked with sediment causing the main channel to split into smaller branching channels or distributaries. The name originates from the Greek for the delta's 'D'-like shape.
Demand: the willingness and ability of consumers to pay for a particular good or service; As long as the supply of goods and services meets the demand, prices remain the same (stable). High demand for land in the CBD from businesses wishing to locate there results in very high land values because supply cannot be increased to meet the demand.
Demographic Transition Model: diagram which shows the relationship between birth and death rates and how changes in these affect the total population.
Demographic transition: the change from high birth rates and death rates to low birth rates and death rates.
Demography: The systematic analysis of population.
Dendritic: Dendritic is a description of a stream which resembles the pattern of a tree.
Dendrochronology: Dendrochronology is the process of studying the age of a full-grown tree by reading the concentric rings on its trunk.
Denitrification: It is a geography term which means conversion of nitrates into nitrogen by the bacteria present in the soil. This makes the soil less fertile.
Densely Populated: An area that is crowded.
Density: A measure of how close together people live in an area.
Denudation: As a term in geography glossary, denudation means removal of soil from the surface layer.
Dependant person: This is either a dependant child, or a person with long-term sickness preventing him/her from working.
Dependency ratio: the ratio between those of working age and those of non-working age. This is calculated as:
Dependent Population: those who rely on the working population for support e.g. the young and elderly.
Dependent Variable: A dependent variable in geography terminology means one that is directly affected by another.
Depopulation: the decline or reduction of population in an area.
Deposition Landforms: Landscape features made up of material that has been deposited by rivers, sea, ice or wind.
Deposition: Deposition is the act of settling down in one place. This geography term is normally used to describe settling down of soil, due to the agent of erosion, in a particular place.
Deposition: The laying down of material carried by rivers, sea, ice or wind.
Depression (cyclone, low, low-pressure area) Area in the atmosphere in which the pressures are lower than those of the surrounding region at the same level. In its development a depression usually has the following phases. A wave (young) depression forms and moves along a front. Mature depressions have well-developed warm sectors and both cold and warm fronts. An occluded depression is that within which there has developed an occluded front.
Depression: The region which has low barometric pressures due to circular movement of isobars, warm front and cold front, inward and anti-clockwise winds is known as depression.
Deprivation: The degree to which an individual or an area is deprived of services and amenities. There are many different types and levels of deprivation included poor and overcrowded housing, inadequate diet, inadequate income and lack of opportunity for employment.
Depth: increases downstream, a result of being joined by a number of tributaries.
Derelict Land: Derelict land is the land which has had a heavy impact of activities such as mining and quarrying and is left neglected.
Derelict Land: waste land with decaying houses and closed-down industry, typical of inner city areas in MEDCs.
Derelict: abandoned buildings and wasteland.
Desertification: the reduction in the fertility of the land as a result of human or natural processes. Causes include overgrazing, over-cropping, gradual destruction of trees for fuel, the use of cattle dung as a fuel, deforestation and climate change.
Desire Line: Desire line connects the movement of people by tracking their origin with their destination on a map.
Destructive Plate Margin: Destructive plate margin is a terminology used in the theory of plate tectonics. The geographic term means, the movement of plates towards each other, during which one is destroyed as it returns to the mantle. The abrasion might be amongst oceanic plates or continental plates. It is always the denser of the two plates which is subducted.
Destructive Wave: It is a powerful wave, which washes away beach material, because of stronger backwash than its swash.
Destructive Waves: found on steep beaches, are steeply breaking and mainly responsible for coastal erosion. Their backwash is much stronger than their swash.
Detached house: a house standing alone (not joined to another) typical of the wealthy suburb zone of a city. (See Burgess).
Detritivore: Detritivore is an organism that feeds on dead material.
De-urbanisation: the process in MEDCs by which an increasingly smaller percentage of a country’s population lives in towns and cities, brought about by urban-rural migration. (See Counter-Urbanisation and Urban-Rural Shift).
Development Area: As a geography term, a development area means an area which is backed by an economic support.
Development Model: Development model is a theory which explains how and why development occurs.
Dew point (dew-point temperature) The temperature to which a given parcel of air must be cooled in order for saturation to occur. When this temperature is below 0 °C, frosts form.
Dew Point: Dew point is the temperature at which air becomes saturated and results in dew.
Dew: Dew is condensation of water on the ground surfaces in winter time or on cold mornings.
Diastrophism: Diastrophism is a process distortion by which the crusts, continents, mountains, depressions, faults and oceanic beds are formed.
Diffluence: Diffluence as a part of geography glossary means breaking off, of a smaller glacier from a larger one, which then crosses a drainage divide.
Dike: It is a wall built to avoid flooding.
Discharge: Discharge is the volume of water flowing through any water body per unit time.
Discharge: the amount of water passing a specific point at a given time. This become larger downstream as a result of the joining of many tributaries. It is calculated as: cross-sectional area x velocity, and measured in cubic metres per second (m³/sec).
Discontinuous Permafrost: Discontinuous permafrost are areas between 50˚North and the Arctic Circle, where temperature varies between -1˚ to -5˚. Some area remains permafrost stretching up to 50 meters in depth, whereas some area remains under little frost due to local warmer conditions like rivers.
Discordant Coast: When a band of differing rocks run perpendicular to a sea, it is known as a discordant coast line.
Dispersal: The process of dispersion or distribution by wind is known as dispersal.
Dispersed Population Distribution: the opposite of a concentrated distribution; the population may be spread evenly over a fertile farming area, rather than concentrated in an urban centre. Dispersed population distributions tend to be of low density.
Dispersed Settlement Pattern: where buildings in a settlement are not clustered around a particular point but are scattered in a random fashion (see linear and nucleated settlement).
Dissolved Load: The materials carried by a river or any water body is known as dissolved load.
Distance Decay: The distance through which ocean waves pass after drifting away from the generating area.
Distributaries: finger-like river channels which branch away from a main river channel in a delta.
Distributary: A branch of a river that flows away from the river and never rejoins it.
Distribution (of a population): where people are found and where they are not found.
Distribution Channel: It is a path or a line through which products are carried to the market.
Distribution: It is the act of distributing or being distributed; the apportionment of resources or any other item such as moving products from manufacturing to the consumers.
Diurnal: It means occurring in a period of 24 hours or which has a daily cycle.
Divergent Plate Margin: A boundary of tectonic plates, as they drift apart and new crust forms from the magma which rises up.
Diversification: switching from farming specialising in a particular product e.g. crop or animal to one depending on a range activities for an income e.g. bed and breakfast, paint-balling, farm zoo, pick-your-own fruit etc. The EU provides grants for farms to diversify to try to reduce the food surpluses resulting from over production.
Division of labour: increased productivity gained when workers specialise in one particular part of the manufacturing process e.g. fitting windscreens in a car plant. They become faster and more skilled.
Dome: A steep-sided mound that forms when very viscous lava is extruded from a volcanic vent. (USGS 2010) An uplifted area of sedimentary rocks with a downward dip in all directions; often caused by molten rock material pushing upward from below. The sediments have often eroded away, exposing the rocks that resulted when the molten material cooled.
Dormitory Settlement: A place or a town, where its residents are daily commuters as they are employed in some other place.
Dormitory Settlement: one where many commuters 'sleep' overnight but travel to work elsewhere during the day.
Doubling Time: Doubling time is the time frame or a period required for doubling of something in value or quantity, e.g. population, inflation.
Draa: A large sand dune that is hundreds of feet in height and runs for miles together.
Drainage Basin: It is an area which is drained by a system of rivers and its tributaries.
Drainage Basin: the land that is drained by a river and its tributaries.
Drainage: removing water from wet land by digging ditches; the water table is lowered, the ground becomes drier and better suited to crops. (See Wet Lands).
Dredging: It is the deepening or widening of a channel by removing sediment from the bottom of a river or sea. This is done to improve navigation or to obtain construction materials.
Dredging: excavating sand and shingle from the sea bed; this can contribute to coastal erosion.
Drift: To be carried along by river or water currents is known as drift.
Drought: A long period defined by low or no rainfall, which has an adverse effect on living conditions.
Drought: A long spell of dry weather resulting in a serious water shortage.
Dry Adiabatic Lapse Rate (DALR): The rate at which atmospheric variable decreases with height is known as the dry adiabatic lapse rate.
Dry farming: A type of farming practiced in semi-arid or dry grassland areas without irrigation using such approaches as fallowing, maintaining a finely broken surface, and growing drought-tolerant crops.
Dry Point Site: A patch of dry ground which is firm enough to build on. It is often near rivers on higher ground above the level of flood danger.
Dry Valley: A valley which does not have a permanent water resource and which is set in chalk or karst dominant topography is called a dry valley.
Dry-point Site: a settlement site on dry land surrounded by low, wet ground; this was good for defence.
Dune: A ridge made by wind blown sand in arid in coastal areas.
Dust Bowl: It is a region rendered dry and arid due to drought and sand storms.