Learn R Part 3: Data Visualization.

   Visualization is pretty important if you are working with data. It is difficult to explain what raw data means to decision makers, you need some kind of data visualization to help you and decision makers to understand data faster and better. I am going to focus on basic data visualization functions of R in this post. Basic graphs can be created really easy in R. Let's start with plot() function.

     I am going to create and array of integers and use names function to give them names, then i am going to call barplot function to create bar graph.

sold <- c(30,40,60,50,46)
names(sold) <- c("Jan",'Feb','Mar','Apr','May')
barplot(sold)

This will create the following bar graph. 

R Fiddle

      Next, Let's try to create a line chart, I am going to keep it simple so we have two arrays one for x which represents the months of a year, and another Y which represents the data. Let's say number of products sold.

 months <- c(1,2,3,4,5,6,7,8,9,10,11,12)
 sold <-c(20,40,50,40,30,60,55,40,60,90,80,90)
 plot(months,sold, type="l")

R Fiddle

       Let's try something more complex, I want to use the perspective plot in my next example. I am going to create a matrix to demo this type of graph. I have multi dimensional array, (10,10) and all of my values are 1 except the one in the center which is 0. Here is my code. I used expand option to shrink the size of the graph.

floor <- matrix(1,10,10)
floor[5,5] <- 0
persp(floor, expand=0.4)

R Fiddle

      R comes with some sample data, one of those datasets named volcano. You can type volcano to see the data. It's multi dimensional array with bunch of numbers. I am going to use the volcano dataset to demo some other graphs in my following demos. Let's start with heatmap.

image(volcano)

R Fiddle

           Let's try to display the volcano with persp function. 

persp(volcano, expand=0.4)

R Fiddle

Do you want to see how the volcano looks like from the sky, we can use contour graph function to do that.

contour(volcano)

R Fiddle

        As you can see, R is pretty powerful when it comes to display the data in a graph. You can customize all of these graphs if you like. But with passing only the data, I think R do a decent job. All of these functions comes with the base version. You don't need to install any special libraries for the graphs i have covered here. Everything I showed here is the really basic functions, check out R Graph Gallery to see some good looking ones.