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Geography: from local to global

De Baripedia


Definition of Geography[modifier | modifier le wikicode]

It is the study of the organization of the Earth's space for descriptive and explanatory purposes. We are interested in forms, functions, practices, but also spatial representations.

There are different approaches and debates in order to define the discipline, its scope and its stakes:

  • The current of spatial analysis seeks to establish a grammar of different spatial forms, therefore is interested and seeks to modernize spatial structures.
  • There are postmodernist approaches that seek to deconstruct categories that would not capture the subtlety and diversity of spatial approaches.

It is also a discipline where there are important theoretical and epistemological debates.

Successive conceptions of the discipline[modifier | modifier le wikicode]

Conceptions of the discipline have evolved considerably over time. Geography was for a very long time a non-scientific discipline because it was descriptive. But extremely useful because it was used to describe parts of the world by dominant societies. It has also accompanied processes of conquest. Geography played a political role in supporting these conquests and prescientific to prescientific descriptions related to these new parts of the world.

This descriptive and accompanying political role, geography continued to be essential in the definition phase of nation-states. Atlas, teachings have been created so that people under the authority of a nation-state know the characteristics of their quality. Also, in the colonization phase, geography was used to define the conquered spaces in a logic of exploitation.

It is only at the end of the 19th century that geography will pass to the stage of explanation. The first laws are problematic insofar as they are positivist reducing reality to alternatives far from reality. This was the period of determinism when geography sought to define development by natural resources and environmental constraints.

Today comes the question of globalization, which partially abolishes distances and authorizes exchanges and communications on a global scale. If the distances disappear for some, on the contrary for others the distances increase.

The different branches and approaches[modifier | modifier le wikicode]

In Geneva, the focus is on political geography and spatial planning.

There are several types of cards:

  • topographic maps also called "road maps": they are produced at different scales and make it possible to apprehend space at different scales. The utility is to situate oneself in space. Generally, they comprise a set of information that compiles information on infrastructures, services, in other words, a set of resources in space is inventoried.
  • thematic maps: they show the spatial distribution of a phenomenon (economic, cultural, political, etc.) such as the distribution of votes in the USA.
  • maps to communicate: they are produced by the world of communication
  • GPS or Google Earth databases: offer cartographic representations that use a continuity of scales. These are databases that are georeferenced or that compile images.

Implantations géographiques[modifier | modifier le wikicode]

On the maps there are a number of localized realities and processes for which the spatial distribution will be reported. They can be represented in three ways:

  • one-time: is represented by a dot
  • surface: is similar to a surface or an area (areolar or surface implantation)
  • linear: in the form of a line
Documentation photographique n° 8009, Villes africaines (auteur : Roland Pourtier) - ladocumentationfrancaise.fr

Comment of the map :

  • surface/areolar: What is represented in a surface or areal way is the size of the population
  • one-time: the points represent the cities at their coordinate point; the size of the circle is proportional to the size of the city or agglomeration.
  • linear: it is the borders of states that constitute the boundary between the different states.

These implementations refer to three logics of presence and spatial diffusion.

Benoit Antheaume et Frédéric Giraut, « Le téléphone mobile, l'Afrique du Sud et ses marges », EchoGéo [En ligne] - Auteur : Frédéric Giraut, 2003.

We are located in Lesotho which is faced with the dependence of coverage to be able to use the mobile phone service. As in Latin America the traditional costume consisted of wool blanket. We make a metaphor with the coverage of mobile phones.

Expansion of GSM coverage in Africa, 2001-2005 par Steve Song sur Flickr

Coverage for mobile telephony may either be absent, as in the Sahara, which is not covered at all, or just punctual. On the other hand, there are some states like Angola that in the 2000s did not have any coverage.

Concerning the cities, it is either a single coverage, or punctual which will allow the development of a network from the original point, so the periphery is gradually integrated.

The progression of coverage can be either concentric or linear. One can cite the Nile Valley or Nigeria, which links the coast to other territories by road. The implantation is thus linear as well as the diffusion of the phenomenon.

There are also corridors under construction in Sudan, Cameroon and northern Congo. In the Maghreb, we see the spread of coverage over a vast area, but also South Africa. On a regional scale, we can also mention the Nile delta.

Access to mobile phones can affect remote populations, especially those who have never had fixed telephony.

Projections[modifier | modifier le wikicode]

When you have a map, it represents a portion of a sphere. It is a curved space that we will project on a plane. It induces deformation. Depending on the type of projection, we will have different deformations depending on the technique. Behind the projection is the challenge of representing a sphere.

Cylindrical projection[modifier | modifier le wikicode]

Projection conique.jpg

For a very long time a cylindrical type of projection was used. It allows to have a representation of the whole world on a cylinder projection.

La projection de Mercator est cylindrique.

Mercator Projection[modifier | modifier le wikicode]

It is said to be compliant, but not equivalent. That is to say that when one bases oneself on a meridian the distances are kept as well as the different parts of the world. What is modified are the surfaces represented, near the equator they have nothing to do with those located near the pole. Higher latitudes are given more importance. So we're going to have more and more surface added.

Projection transverse de Mercator du monde (bandes de 20°) centrée sur 0°E, 0°N.

The tropical zone is underrepresented, while the temperate zone is underrepresented. As a result, a much larger dimension is attributed to what it is of the temperate zone compared to the tropical zone.

Projection of Peters[modifier | modifier le wikicode]

It was designed at the beginning of the 20th century on a cylindrical base, but limiting the addition of area to remote latitudes.

Projection de Peters de la Terre.

The problem is that it stretches the intertropical zone in height. The quality is to reproduce the dimensions to each part of the world that correspond to each real part.

Conical projection[modifier | modifier le wikicode]

It represents only one hemisphere. In principle, it can only represent a part of the globe.

Projection conique conforme de Lambert

Fuller's projection[modifier | modifier le wikicode]

We start from a cylindrical projection, but extended. The interest lies in the fact that the proportionality of the surfaces is respected. There is little deformation, but to extend it to the entire globe we had to tear the planes and make cuts in the oceans and make conical projections. It is centred on the northern surface which represents the realities from this centre. It shows how we have a first circle constituted by the dominant countries. Then there are the peripheries which are linked by a privileged link with the triad of dominant countries.

Projection de Fuller en animation.

Planisphere of Stuart Mac Artur (1972, Melbourne)[modifier | modifier le wikicode]

This map is the vision of the antipodes that seeks to reverse the representation of the world in two ways:

  • by changing the orientation of the card by inverting the poles. We use a reference meridian opposite to the reference meridian which is the Greenwich meridian. Throughout this world, represents the world above and changes the meridian of references;
  • the projection is modified between the others and low altitudes.
Projection de McArthur (1979), le sud en haut et centrée sur l'Océanie.

Map by anamorphosis[modifier | modifier le wikicode]

Here, an area proportional to their actual population is given; this reflects the dimensional hierarchy according to their overall population.

Cartogramme par anamorphose de surface représentant la répartition de la population dans les états membres de l'Union européenne (Mars 2008).

Annexes[modifier | modifier le wikicode]

References[modifier | modifier le wikicode]