A Bubble chart is a variation of a Scatter chart in
which the data points are replaced with bubbles. A Bubble chart can be used
instead of a Scatter chart if your data has three data series, each of which contains a set of values. In
a Bubble chart, the size of the bubbles is determined by the values in the
third data series. Bubble
charts are often used to present financial data. We are not limited to the
circular markers provided by default in bubble charts. We can use the technique
described in custom chart series markers to
use any shape you want for the markers. Motion charts are animated
bubble charts. They track the
performance of important things over time (in two dimensions). This
is chart with 4 dimensions. But not all data with 4 dimensions can be plotted
as a motion chart. One dimension has to be time, and another has to be linked
to the importance of the item. we can also turn any bubble chart into a
quadrant chart. This is useful if you want to categorize your data a little
further by using a common layout like it is used in a SWOT or market
attractiveness analysis.
Making bubble charts in R:
Step 1:
Download R and load the data into R for which a bubble chart
has to be created. A .csv file with data in it can be read into R using the
command read.csv
Step 2:
Circles can be drawn using the command symbols() and the
values for x-axis, y-axis and bubbles are given. By default,
symbols() sizes the largest bubble to one inch,
and then scales the rest accordingly. It can be changed by using the inches argument.
Step 3:
To change the color of the bubbles we can use the
arguments fg and bg to change the foreground and background colors
respectively.
Eg:
symbols(table$cloumnname1, table$columnname2, circles=radius,
inches=0.35, fg="white", bg="red", xlab=" ", ylab=" ")
The xlab and ylab arguments are used to name the X-axis and
Y-axis.
The shapes of the bubbles can be changed by changing the values
in the “inches” argument. This changes the shape of the circle to square or any
other shape.
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