Introduction
The data of the annual currency exchange rate was acquired from the Food and Agriculture Organization of the United Nations website. The data set includes exchange rates for 214 countries to U.S. dollars, and the data series start from 2006 to 2017.
The data was downloaded as a csv. format, and the data was cleaned in the excel sheet as the data set obtained from the website was very neat. The data was presented as normalized format where every variable forms a column and categories of the same variable are not split across columns. The data was cleaned such that only Area Code, Currency Code, Year and Value were remained as follow:
The data was cleaned such that only Area Code, Currency Code, Year and Value. The file was saved as xls. format and was imported to the Tableau Public to create interactive data visualizations for the web.
Method
The first thing that might be interesting to look at will be the comparison of currency exchange rate of different countries in different year. In order to do this, the data type has to change to string so that the year will be used as text rather than numbers, allowing to create a slider bar of the years afterwards. In order to compare the currency exchange rate of different countries at the same year, a horizontal bar graph is developed where the annual exchange rate is plotted on the x-axis representing the rates across different countries. A filter is created for the years which allows to view the demand data by year, and in this case, from 2006 to 2016.
The bar chart was sorted with the countries that has the highest exchange rate at the top and the lowest at the bottom. The reason of sorting the bar chart in descending order is because this makes it easier to analysis even though the bar lengths are close. If the chart is not sorted, it may not be obvious.
The comparison of currency exchange rate of different countries in different year using a bar chart.
I was using the International Crime Statistic of Robbery chart from the Knoema website as a reference. A bar chart is used to compare the robbery rate of different countries from 2003 to 2013, and the values are included in each bar. Since my currency exchange rate is an interactive bar chart, the value of each exchange rate will be shown when the cursor points to it, therefore, I did not display the value in the bar chart.
International Crime Statistic of Robbery chart from the Knoema website
The next thing that might be interesting to look at will be the comparison of currency exchange rate of the same country over a period of time. In this case, a line chart is used to display the how the exchange rate of a country changes over a period of time. The reason of using a line chart instead of bar chart to show the relationship is that the direction of the lines create a very straight forward metaphor for the data: an upward slop indicates where the exchange rate has increased, and a downward slope indicates the rate has decreased.
The line chart is plotted where the exchange rate is on the y-axis over the year from 2006 to 2016. A line chart is created for each country separately, and this time, a filter is created for the countries which allows one to view the chart by selecting the country. I did not create a combined line chart for all the countries as there will be too many lines and make the chart complicated and hard to decipher.
The line chart is plotted where the exchange rate is on the y-axis over the year from 2006 to 2016.
A tutorial line chart from a blogger and a line chart from Knoema website are used as the reference for my currency line chart. The line chart created by the blogger shows the unemployment rate in Europe and the percentage rates of 17 countries have been displayed in a single line chart. Different colors have been used to represent different countries. Although the rising unemployment rates for most counties is clear, it is very difficult to distinguish 17 lines in 17 different colors. The colors and overlap create a visual burden, and moreover, this graph will not work for a color blind viewer. It will even be more difficult if this is use in my currency exchange rate graph when there are 214 countries.
Tutorial line chart from a blogger, Jim Wahl
On the other hand, the line chart from the Knoema website shows the currency exchange rate over a period of time span of one country instead of combining the countries together. It will be especially useful to show the line graph individually when the currency exchange rate are very different from one another. In the following example, the exchange rate for 1 USD to EUR is within one digit while the exchange rate for 1 USD for JPY is two or three digits. Since my data set are comparing the currency exchange rate of 214 countries, it will be better to display the line chart per country rather than combining them together in one chart.
Line chart from Knoema website
Finally, I have adjusted the color of the charts. I have used gray as the font color, and used pink as the bar and line color so that the pink will stand out when viewing the dashboard. I did not use multiple colors as I do not think it is necessary in this case because the charts are just showing a single value at one time. The dashboard is shown as follow:
Dashboard of Annual Exchange Rates from 2006 to 2016
Link: https://public.tableau.com/profile/guida5123#!/vizhome/new3_5/Dashboard1
Discussion
In the future, I would like to create a line chart that can select multiple counties and show multiple series lines on the same graph for allowing one to compare different currency exchange rate of different countries. In this case, one can select multiple lines if they wish to compare the rate of multiple countries.