“Population is the point of reference from which all other phenomena are observed and from
which they all, singly and coll...
Merits of population density
1 Population density has been developed as a means, partly of accessing over
population and u...
2 Agricultural density is a modified concept of population density. In this, densities are
calculated for agricultural pop...
Objection
CDP is calculated as 100B . Naturally, these variables are not easy to define accurately, but
the CDP is a usefu...
Objection
This concept ignores the size of the room, which is very important factor in accessing room
densities. Persons p...
of 5

Population Density and its Modified Concepts

Population Density and its Modified Concepts
Published on: Mar 4, 2016
Published in: Environment      
Source: www.slideshare.net


Transcripts - Population Density and its Modified Concepts

  • 1. “Population is the point of reference from which all other phenomena are observed and from which they all, singly and collectively, derive significance and meaning. It is population which furnishes the focus.” Concept of population density is first time used in 1837 by Henry Drury Harness in a series of maps. He describes this concept as! “Relation between numbers of people to the space occupied by them.” We can define population density with respect to two approaches. 1. Aggregative approach or ranking method (this approach covers the whole population of an area for study). 2. Distributive approach or percentage method (atomization or decompose the whole figure to focus on single thing that is atomize an area into universe and sub-universe). Density of population can also be defines as number of people per unit area. This can be expressed with a simple formula given below. When population (P) increase, density (D) of population tends to be increase providing the area (A) remains constant. In agricultural countries we take density of population as number of people per hectare to per acre of land known as agricultural density. Population is constantly changing in 190 Less Develop Countries (LDCs). Only in 14 Most Developed Countries (MDCs), population appears to be same but not constant. Population distribution is a phenomenon. Distribution of population reveals the interplay of a vast multitude of physical and man-made phenomena. Distribution of population acts as a master-threat keep-able of weaving into a coherent pattern, the otherwise disparate strand of phenomena over the surface of the earth.
  • 2. Merits of population density 1 Population density has been developed as a means, partly of accessing over population and under population of an area, by comparing its existing and potential densities. 2 Population density is a useful abstraction, assisting in the analysis of the diversity of man’s distribution in the space. 3 Crude density of population is the man/land ratio, have more significance for the spatial comparison and differentiation of much smaller units. 4 Population density is useful for obtaining an index for the purposes of areal comparison. Modifications in the concept of population density As people are congregation into more and smaller areas and leaving much of the earth surface sparsely inhabited, it was inevitable that refinements of density concept should be made, by modifications to the numerator, the denominator or both. 1 The Dasymetric technique devised by Wright is a modified concept of population density. It is a method of drawing a map to show density of population, departing from large administrative units with mean figures, and using reasonable guesses to produce realistic categories, for which densities can be estimated. In Dasymetric technique, densities are calculated only for inhabited areas, the remaining areas being left blank on population maps. In Dasymetric technique, densities are also calculated for cultivable areas, and are known in France as physiological densities. They are preferable for the crude densities for a country like Egypt, where 96% of populations inhabit about 4% of the total area. Objection Physiological densities must be used judiciously, as land which is not cultivable is not necessarily unproductive. Moreover, in some countries statistics of cultivable land are not available; in others cultivable and cultivated land are not distinguished.
  • 3. 2 Agricultural density is a modified concept of population density. In this, densities are calculated for agricultural population. In Britain, where less than 5% of the active population are employed in agriculture, the agriculture density may be of greater interests than densities of the total population per unit of cultivable or cultivated land. Objection It is not easy to define agricultural population. Do we include only active males employed in agriculture, or should we also evaluate the work of women, children and old people, all of whom may play a very useful part in some countries? 3 Another modified concept of population density, introduced by the French geographer Vincent suggested in 1946, called comparative density. It is a type of physiological density, where the total population is related to land area, weighted according to its productivity. This method has been carried a stage further by employing a standard land use unit, termed, “a hectare of arable equivalent”. All arable land is assumed to be uniform value; orchards and gardens are three times as valuable as arable land; meadow land has only two-fifth of the value and pastures only one-fifth. Objection It is doubtful whether calculations of this sort throw more light on the problem of comparison of population densities, as the value of agricultural land varies enormously. 4 In the perspective of environmental conservation, Allan has proposed a measure of Critical Density of Population (CDP) which he defines as “the human carrying capacity of an area in relation to a given land use systems, expressed in terms of population per square mile; it is the maximum population density which a system is capable of supporting permanently in that environment without danger to the land”. Three sets of information are used to calculate in CDP: (A) the percentage of land cultivable by traditional methods, (B) The land use factor or the relationship between duration of cultivation and fallow, (C) cultivation factor or acreage planted per capita each year.
  • 4. Objection CDP is calculated as 100B . Naturally, these variables are not easy to define accurately, but the CDP is a useful index in the study of subsistence economies. 5 The notion of economic density is another modified concept of population density. It was proposed in 1934 by the French demographer Simon as a formula. Where is the index of population size and is the general index of production for the same year. Simon believed that he had discovered an index capable of determining the optimum density population in relation to a base period. As other denominators in his formula, Simon also proposed (A) the general index of consumption, (B) the general index of all economic activities, (C) average income per person, (D) standard of living and (E) available diets. Objection George has insisted that such measures of economic wealth are inadequate unless examined in the light of the different economic systems and of social evaluation. Furthermore, the calculation of these denominators is vitiated by changing international conditions. 6 The concept of urban population density may use a variety of denominators including (A) total urban area, (B) built-up area, (C) net area of occupied dwelling lots and (D) gross area of occupied dwelling lots. Objection These densities throw little light on the congestion within towns, where vertical expansion partly invalidates man/land ratios and gives no information about concentration of people within buildings, houses and rooms. 7 Another modified concept of population density is “room densities”. It includes average number of persons per rooms and it is a useful index of density of occupation as well as housing conditions.
  • 5. Objection This concept ignores the size of the room, which is very important factor in accessing room densities. Persons per room data are normally limited to private households, the size and the composition of which are not taken into account by room densities. Census reports usually provide data of the number and the percentage of private households living at different room densities. In this, only habitable rooms are counted including living rooms, bed room, kitchens but excluding sculleries, bathrooms, etc. 8 Nutritional density is another modified concept of population density. It is the measure of how much nutrition can be produced from land. It is a ratio between the total population and the amount of land under cultivation in a given area. If cropped area is 1 acre then u can get three times higher yield from the same farmland. The World Health Organization reviews scientific and operational issues related to human nutrition, specifically when developing world populations are impacted. 9 Settlement density is a modified concept of population density. It is a measure represents the amount of area in a country for each city with 100,000 people or more. In the United Kingdom, there are about 13,000 square miles for each city. Advantage of modified concept Thus the concept of population density has been extended beyond the scope of geography. Every modified concept of population density has its own merits and demerits. We should take as much benefits as we can from them, and try to avoid their demerits.

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