**Graphs and population**

**(Explanations were taken from Richmond's textbook Geography and History, 2004.ISBN:84-294-9216-X ) **

Maths web task

Maths web task

**What are graphs? Have a look at this visual explanation of them. Different types of graphs are used to represent demographic data. Let's have a look at them:**

**THE LINE OR LINEAR GRAPH **

** Through one or more lines it represents the values of a variable. It is the most commonly used to represent the evolution of a variable over a period of time.**

** Located on the horizontal axis, is the time variable ( for example the years), and on the vertical axis, the variable that represents, for example, the number or inhabitants. The values are marked at the corresponding height on the vertical axis and then they are joined together with a line.**

**It represents the values of a variable in a given spatial unit (continents, countries, etc) through columns or bars, which have proportional length to the quantity they represent. **

**This one represents the countries with more population density. **

**Countries, years are located on the horizontal axis and the corresponding values are marked with bars according to the vertical axis. **

**THE PIE GRAPHS **

**It represents, through sectors proportional to the value they represent, the distribution of a phenomenon: for example the distribution of the world's population.**

**It is easy to draw: If 100 (%) is 360º, 10% is at X. X are the degrees of the circumference obtained.**

** If you would like to have more practice on this topic,click here or here **

**EXERCISES: WHAT GRAPH/S WOULD YOU USE IN THESE SITUATIONS? **

**1. How would you represent the evolution of infant mortality in Senegal from the years 1995 to 2005? Draw it in your notebook.****2. How would you represent the countries that receive most inmigrants in Europe?****3. How would you represent the percentage of African, Asian American or European inmigrants in a country? Click on this link and choose The United Kingdom. Then find the data about the total number of immigrants that the country receives.ARRIVALS: (Inflow of foreign-born population by****country by year) Then get the percentage of African, American, European and Asian migrants in the year 1991 and draw the chart or graph in your notebook.****4.****How would you represent the distribution of rural and urban population in an Autonomous Community?****5. How would you represent the evolution of immigrants in Europe from the year 1990 to 2005? Click here and get the estimated number of international migrants at midyear. Draw the chart in your notebook.****6. Transform this bar chart with the top ten countries with international immigrants into a pie chart. Calculate the percentages and draw it in your notebook.**-
**Back to introductory page**