Histograms

Histograms are a very important type of plot as it lets you see the frequency in which certain values appear in your data. This type of plot is also call a frequency distribution. To create a histogram in R, you use the command hist(x), where x, is the vector of data you want to plot.

Lets create a frequency distribution of the GDP (Gross Domestic Producto) of countries in the world, using the csv file we loaded earlier,

#lets reload the data, just in case you have not loaded it
GDPData=read.csv("https://raw.githubusercontent.com/Camilo-Mora/GEO380/main/Datasets/Countries_GDP.csv")

head(GDPData)   #now lets check the data

##       country continent year gdpPercap
## 1 Afghanistan      Asia 1952  779.4453
## 2 Afghanistan      Asia 1957  820.8530
## 3 Afghanistan      Asia 1962  853.1007
## 4 Afghanistan      Asia 1967  836.1971
## 5 Afghanistan      Asia 1972  739.9811
## 6 Afghanistan      Asia 1977  786.1134

hist(GDPData$gdpPercap) #now lets create a frequency of number of countries by GDP

Just as with the scatterplot, you can improve the appearance of the figure. Lets start with the axis name.

hist(GDPData$gdpPercap, xlab="GDP countries in USDollars")

What about that title?. Not pretty, ah?. That is a default in R. To remove it, we set the “main” parameter to NULL, like this:

hist(GDPData$gdpPercap, xlab="GDP countries in USDollars",main=NULL) 

Most journals do not allow you to put tittles in your plots.

If you want to rather keep the tittle, but have a different tittle, you replace NULL with the title you want, like this:

hist(GDPData$gdpPercap, xlab="GDP countries in USDollars",main="Countries of the World")