Visualizing Custom Data on a Choropleth Map
Introduction
This application generates a choropleth map visualizing the average number of children born to a woman in a number of European countries for the calendar year 2015.
Data source: Eurostat - http://ec.europa.eu/eurostat/tgm/table.do?tab=table&init=1&language=en&pcode=tsdde220 (accessed 9 April 2017)
Data Description: The mean number of children that would be born alive to a woman during her lifetime if she were to survive and pass through her childbearing years conforming to the fertility rates by age of a given year.
Import fertility rate data
First a DataFrame is created to contain the data set. Note that this data is for the year 2015.
FertilityData := Import("datasets/fertility_rates.csv", base = datadir);
FertilityData≔Fertility Rate - 2015Belgium1.7Bulgaria1.53Czech Republic1.57Denmark1.71Germany1.5Estonia1.58Ireland1.92Greece1.33......
Generate a world map and restrict the view to Europe
The WorldMap command creates a WorldMap object that can be used to display maps of the world in various ways.
europeMap := DataSets:-Builtin:-WorldMap():
The SetView command restricts the view frame for the World map to a given area.
SetView(europeMap,-11,36,32,87):
Define the colors used to shade the map
In the following section, we define two colors to be used to generate the gradient in the ChoroplethMap.
Lowest fertility value:
c1 := ColorTools:-Color("RGB",[0/255,55/255,0/255]);
c1≔⟨RGB : 0 0.216 0⟩
Highest fertility value:
c2 := ColorTools:-Color("RGB",[230/255,230/255,150/255]);
c2≔⟨RGB : 0.902 0.902 0.588⟩
Generate a choropleth
The ChoroplethMap command generates a map that is shaded in proportion to the measurements for the displayed variable, the fertility rate. The plots:-display
FertilityMap := ChoroplethMap(europeMap, FertilityData, [c1, c2], mapdata=fine, watercolor="White"):
Additional plot options can be added using the plots:-display command:
plots:-display(FertilityMap, axes = none, size = [800, 800], title = "Number of Children Per Female (2015)", titlefont = [Arial, Bold, 18]);
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