Monday, 29 October 2012

Paddy fields in Indonesia

Terraced rice paddy fields in Bali, Indonesia.

Saturday, 27 October 2012

Human geography and physical geography

Geography is the study of natural and human constructed phenomena from a spatial perspective. Geography has two main sub disciplines:

Human geography

Human geography includes such subjects as demography, human settlements, transportation, recreation and tourism, resources, religion, social traditions, human migration, agriculture, urban systems, and economic activities.

Physical geography 

Physical geography is concerned with the study of the Earth’s atmosphere, biosphere, hydrosphere, and lithosphere from theoretical and applied viewpoints.

Thursday, 25 October 2012

The Delta Works

The Netherlands is a geographically low-lying country. About 27% of The Netherlands and 21% of its population located below sea level, and 50% of its land lying less than one metre above sea level.

Most of the areas below sea level are man-made, caused by centuries of extensive and poorly controlled peat extraction, lowering the surface by several meters. Even in flooded areas peat extraction continued through turf dredging. From the late 16th century land reclamation started and large polder areas are now preserved through elaborate drainage systems with dikes, canals and pumping stations. Much of the Netherlands is formed by the estuary of three important European rivers, which together with their distributaries form the Rhine-Meuse-Scheldt delta.


The Delta Works

The Delta Works is a series of construction projects in the southwest of the Netherlands to protect a large area of land around the Rhine-Meuse-Scheldt delta from the sea.

The Delta Works consist of dams, sluices, locks, dikes and storm surge barriers.


A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water.

Example of a dam: The Haringvlietdam.


A sluice (from the Dutch word "sluis") is a water channel controlled at its head by a gate. 

Sluice gates commonly control water levels and flow rates in rivers and canals. A sluice gate is traditionally a wood or metal barrier sliding in grooves that are set in the sides of the waterway.  

Example of a sluices: 
The sluices of the Eastern Scheldt storm surge barrier.


A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is the chamber itself (usually then called a caisson) that rises and falls.

Locks are used to make a river more easily navigable, or to allow a canal to take a reasonably direct line across land that is not level.

Example of a lock:


The modern word dike or dyke most likely derives from the Dutch word "dijk". Dyke or dike may refer to: 
a natural or artificial slope or wall to regulate water levels. A dike is called levee in American English.
A dike / levee is an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels. It is usually earthen and often parallel to the course of a river in its floodplain or along low-lying coastlines.

Example of a dike:

Storm surge barriers

A storm surge barrier is designed to protect the Netherlands from flooding. The aim of the  storm surge barriers is to shorten the Dutch coastline, therefore reducing the number of dikes that had to be raised.

The Eastern Scheldt storm surge barrier (de Oosterscheldekering), between the islands Schouwen-Duiveland and Noord-Beveland, is the largest of the 13 Delta works series of dams, designed to protect the Netherlands from flooding. The construction of the Delta Works was in response to the Flood of 1953.

The Oosterscheldekering was initially designed, as a closed dam, but after public protest huge sluice-gate-type doors were installed. Thesesluice-gate-doors are normally open, but can be closed under adverse weather conditions. In this way the saltwater marine life behind the dam is preserved and fishing can continue, while the land behind the dam is safe from the water. 

Example of a storm surge barriers (The Eastern Scheldt storm surge barrier):

The "Maeslantkering" is the final protection work of the Deltaworks. Situated in the main access channel of the Port of Rotterdam it is usually in open condition. It has been designed to withstand a severe storm occurring once every 50 years.

Example of a storm surge barriers (The Maeslantkering storm surge barrier near Rotterdam during a test closure):

The aim of the dams, sluices, and storm surge barriers was to shorten the Dutch coastline, therefore reducing the number of dikes that had to be raised.

Saturday, 20 October 2012

1 February 1953

For centuries, the inhabitants of the Netherlands have had to protect themselves against the sea and the rivers. The low-lying parts of the country, which are in fact the delta of three major rivers (the Rhine, the Maas and the Waal), have suffered disastrous flooding on many occasions. Dwelling mounds ('terps'), dikes, windmills, sluices and dams have all been used in the struggle against the waters. For centuries, things have gone well. 

The Netherlands were still rebuilding from the detructive second worldwar and forgot to spend money on the so necessary dikes. And then, in the night of 31 January to 1 February 1953, a combination of a spring flood tide and a hurricane-force northwesterly storm suddenly leads to catastrophe. 

The first flood
On the night of Saturday, 31 January to Sunday, 1 February 1953, the KNMI (the Royal Dutch Meteorological Institute) warned to expect a dangerous high tide and a severe storm from the north-west. The high tide was a spring flood tide. The storm continued to rage with wind-forces of 12 (Beaufort) from the north-west. The storm ripped along the coast. Many places were already in trouble. About 2 am, the first water flowed over the dikes. The dikes began to burst about an hour later. The lower and less well-maintained dikes were the first to go. 

Houses collapsed and were swept away by the current. The rising waters even caused the total destruction of some small villages. Small villages were obliterated by the water. Not a house was left standing. Wherever the water went, people fled to higher-lying areas. To the dike, to the attic, to the roof. 

And they waited fearfully for dawn to break, in the hopes that the flood waters would recede.
Initially the water receded, after all, it was low tide again. Some people then used that moment to flee from their farms to higher-lying village centres. Individual rescues began. People in boats went along the houses picking up people and setting them off in safer places.
Large-scale attempts at rescue organized by outsiders were not yet underway. And at the end of the morning, the water began to once more.

The second flood
The second flood on Sunday afternoon was the worst. The water rose even higher than it had the night before. There was now only one option left: to get up and out onto the roof. Many of the houses that had withstood the night now collapsed. The water simply lifted the roofs off the walls. People drowned, others got stuck. Around five o'clock it grew dark. For thousands of people in the disaster area it was the beginning of a second night of wet and cold and thirst in attics, on roofs, crowded together on the dikes or in higher-lying houses.
Throughout Sunday, February 1st 1953, there was very little help from outside. A few reconnaissance flights were carried out over the disaster area. The raging storm prevented large-scale attempts at help from the air. However, even after a day, people were still not aware of the full extent of the disaster. No one knew that larger parts of Zeeland had virtually disappeared under water.

More rescue operations got underway on Monday, 2 February. The first villages at the edges of the disaster area were evacuated. On the islands, the only rescuers were still individuals with boats. Fishermen, especially, managed to free many people from their perilous positions. 
It was not until Monday 2 February that the first relief packages could be dropped. Tuesday was the turning-point. Only then did the rescue get well underway. Victims were evacuated from the disaster area.

Hundreds of ships brought aid workers to the disaster area. Food was dropped and helicopters were put into action. By Tuesday evening the disaster had practically ended.

In the night of 31 January to 1 February 1953 more than 1800 people drowned, thousands of farm animals were lost and 150,000 hectares of land were inundated.  The nation was stunned by the extent of a disaster unparalleled for centuries. The disaster prompts the launch of a major plan to protect the Dutch Delta (The Delta Works).

Friday, 12 October 2012

Tropical rainforest

A tropical rainforest is an ecosystem type that occurs roughly within the equatorial zone between the Tropic of Cancer and Tropic of Capricorn (roughly within 23.5 degrees north or south of the equator).

This ecosystem experiences high average temperatures and a significant amount of rainfall.
An ecosystem is a system existing in a particular region, at a variety of scales, where organisms exist in communities and interact with the abiotic environment around them. The rainforests are home to more worldwide species than all other biomes added together. About 80 percent of the world's known biodiversity could be found in forests.

Rainforests can be found in Asia, Australia, Africa, South America, Central America, Mexico and on many of the Pacific, Caribbean, and Indian Ocean islands. 

Rainforests are divided into different layers, with vegetation organized into a vertical pattern from the top of the soil to the canopy. Each layer is a unique biotic community containing different plants and animals adapted for life in that particular layer.

Rainforest ecosystems are characterised by heavy convectional rainfall, high humidity, lushness of vegetation and nutrient-rich but shallow soil. These factors give rise to a unique water and nutrient cycle. 

The rainforest nutrient cycling is rapid. The hot, damp conditions on the forest floor allow for the rapid decomposition of dead plant material. This provides plentiful nutrients that are easily absorbed by plant roots. However, as these nutrients are in high demand from the rainforest's many fast-growing plants, they do not remain in the soil for long and stay close to the surface of the soil. If vegetation is removed, the soils quickly become infertile and vulnerable to erosion.

If the rainforest is cleared for agriculture it will not make very good farmland, as the soil will not be rich in nutrients.

Thursday, 11 October 2012

Shifting cultivation

The traditional way of life in the equatorial rainforests depended very much on the flora and fauna of the area. A common type of farming is "shifting cultivation".

Shifting cultivation  is a farming system in which a small tribal group cuts and burns the natural vegetation before cultivating the land. After a number of years the land becomes depleted and the group moves to a new area.

 The original land will recover after a period and the group usually rotates through three or four locations.

Despite appearances, the rainforest soils are not very fertile. The heavy rainfall leaches out the important nutrients from the soil and sometimes the whole topsoil itself can be eroded by the tropical downpours. The native people realised this and so would clear an area of forest, plant crops such as manioc and cassava, and after 3 or 4 years when the soil was losing its fertility would move on to a new patch of forest, which would be cleared and cultivated.

Wednesday, 10 October 2012

Gated community

A gated community is a housing estate containing controlled entrances for pedestrians, bicycles, and cars. Gated communities are often characterized by walls and fences. 

Some gated communities are staffed by private security guards and are often home to high-value properties. Several gated communities are secure enough to resemble fortresses and are intended as such.

[The next video shows a gated community in Colorado.]

Gated communities usually consist of small residential streets and include various shared amenities. For smaller communities this may be only a park or other common area. For larger communities, it may be possible for residents to stay within the community for most day-to-day activities. 

Some gated communities are set up as retirement villages.

[The next video shows a gated community in Berlin.]

Tuesday, 9 October 2012

Why do people migrate?

What are the causes of migration?

Saturday, 6 October 2012

Industry - keywords

Assisted area

An area that receives government help to attract industry
Capital intensive
An industry that spends a lot of money on equipment and machinery, and employs few workers

Enterprise zone
A small area that receives special government help to attract industry.

Extractive industry

Quarrying and mining
Footloose Industry

Industry  that is not tied to a particular location
Greenfield site

Land that has not previously been built on
Heavy Industry
Making large, heavy goods using raw materials such as coal and iron e.g. shipbuilding

High tech Industry
One that uses advanced equipment to make goods e.g. computer chips

Industrial estate
A planned industrial area, often with readymade factory units

Industrial inertia
When an industry stays in an area after the reasons for it being there have gone

Labour intensive
An industry that requires a lot of workers

Light industry

Making small goods with small amounts of raw materials e.g. jewellery
Primary industry

Industry which collects resources provided by nature e.g. farming, forestry, fishing and mining.
Raw materials

Items used to make another product
Secondary Industry
A manufacturing industry (make)

Service industry
Provides a service to people or other industries e.g. transport, retail. Also known as tertiary industry (serve)

Sunrise industry

A new, growing industry e.g. electronics.
Sunset industry
 An old, declining industry e.g. shipbuilding.

Friday, 5 October 2012

Migration into Western Europe

Migration into Western Europe in the 1990s.

Two main types of energy resources

Renewable energy
There are a range of renewable energy resources available. These are solar, wind, wave, tidal, geothermal and hydroelectric.

Thursday, 4 October 2012

Long-term mean precipitation by month

Animation of the long-term average precipitation by month (mm/day and in/day), based on 1961-1990 data. 

World map on a dodecahedron

Basically, the world is a sphere (the shape of a ball), and a map is a flat surface. It's difficult to take a sphere and attempt to form it into a flat surface, since a sphere is a curved object, and a map is completely flat.

Say for example that you have a globe, and you wanted to wrap it in a sheet of paper. The globe is the Earth, and the sheet of paper is a map of its surface. If you tried it, you would find that it is extremely hard to do this.

Likewise, if you've ever peeled an orange, you've found that you can't lay it on a flat surface without tearing it. This is actually just the opposite problem of gift-wrapping the ball. Here we're trying to take a spherical surface and turn it into something flat.

This is also exactly the problem that the mapmaker faces.
There are a dozen different kinds of maps for the Earth, each one using a different pattern or technique. None of them are the "true" map of the Earth, but some come very close.

You can use a dodecahedron to produce a world map. A dodecahedron is a polyhedron with twelve flat faces.

A world map on a dodecahedron is a projection of a world map onto the surface of a dodecahedron, which can be unfolded and flattened to two dimensions.

Wednesday, 3 October 2012

U.S. Population distribution by county

The next map shows the U.S. population distribution by county in 2010.

Percent ethnic groups in the United States by country

Percent White population by county:

Percent Black population by county:

Percent Hispanic population by county:

Percent Asian population by county:

Population change in the United States (counties)

The next map show the U.S. population change, by county 2007 to 2008.

Population projections of the United States (1960 - 2050)

The population of the United States, by racial and ethnic groups.

2050 (projected)

Population projections of the United States: 1960 - 2050.

180 million
205 million
227 million
249 million
274 million
296 million
307 million
438 million

If current trends continue, the population of the United States will rise to 438 million in 2050, from 296 million in 2005, and 82% of the increase will be due to immigrants arriving from 2005 to 2050 and their U.S.-born descendants.

Of the 117 million people added to the population during this period due to the effect of new immigration, 67 million will be the immigrants themselves and 50 million will be their U.S.-born children or grandchildren.

Other key population projections

  • Nearly one in five Americans (19%) will be an immigrant in 2050, compared with one in eight (12%) in 2005. By 2025, the immigrant, or foreign-born, share of the population will surpass the peak during the last great wave of immigration a century ago.

  • The major role of immigration in national growth builds on the pattern of recent decades, during which immigrants and their U.S.-born children and grandchildren accounted for most population increase. Immigration’s importance increased as the average number of births to U.S.-born women dropped sharply before leveling off. 

  • The Latino population, already the nation’s largest minority group, will triple in size and will account for most of the nation’s population growth from 2005 through 2050. Hispanics will make up 29% of the U.S. population in 2050, compared with 14% in 2005. 

  • Births in the United States will play a growing role in Hispanic and Asian population growth; as a result, a smaller proportion of both groups will be foreign-born in 2050 than is the case now.

  • The white population will increase more slowly than other racial and ethnic groups; whites will become a minority (47%) by 2050.

  • The nation’s elderly population will more than double in size from 2005 through 2050, as the baby boom generation enters the traditional retirement years. The number of working-age Americans and children will grow more slowly than the elderly population, and will shrink as a share of the total population.