A stacked dotplot is a type of plot that displays frequencies using dots, piled one over the other. Mainly 2 methods are there, to make a stacked dot plot and both of them are discussed in this article.

### Method 1: Using stripchart()

So, using the first method, stripchart method, to create our stacked dot plot. For instance, if we don’t have a set of values, we can even make them, serve our purpose. We would create a set of values that would contain numbers ranging from 0 to 30, including both the ranges too, i.e., the set of values would also include 0 and 30. After creating the set of values, we would plot our stacked dotplot based on those values. We would use the function set.seed(), to reproduce a particular sequence of ‘random’ numbers. stripchart produces one-dimensional scatter plots (or dot plots) of the given data.

Syntax:stripchart(x, …)

**Example:**

## R

`# sets the starting number used ` `# to generate a sequence of random ` `# numbers` `set.seed` `(0)` ` ` `# shows 100 such randomly generated` `# numbers from 0 to 20` `data <- ` `sample` `(0:30, 500, replace = ` `TRUE` `)` ` ` `# creates the stacked data plot` `stripchart` `(data, method = ` `"stack"` `)` |

**Output:**

But, the dot plot which we made, is not so pleasing, like the whole stacked dotplot is somewhat above the X-axis, so now we are going to edit it a bit, to make it look more interesting.

**Example:**

## R

`# sets the starting number which is used` `# to generate a sequence of random numbers` `set.seed` `(0)` ` ` `# shows 100 such randomly generated ` `# numbers from 0 to 20` `data <- ` `sample` `(0:30, 500, replace = ` `TRUE` `)` ` ` `# creats the stacked dotplot, given ` `# some more parameters to make the` `# stacked dotplot look more attractive` `stripchart` `(data, method = ` `"stack"` `, at = 0, ` ` ` `pch = 16, col = ` `"darkgreen"` `,` ` ` `main = ` `"Stacked Dot Plot"` `, ` ` ` `xlab = ` `"X-Axis Values"` `, ` ` ` `ylab = ` `"Y-Axis Values"` `)` |

**Output:**

### Method 2: Using geom_dotplot()

In a dot plot, the width of a dot corresponds to the bin width (or maximum width, depending on the binning algorithm), and dots are stacked, with each dot representing one observation.

Syntax:geom_dotplot()

Parameter:

The diameter of the dots relative to binwidth, default 1.dotsize:how close to stack the dots. Default is 1, where dots just touch. Use smaller values for closer, overlapping dots.stackratio:interior colour of the dots in the stack.fill:exterior outline colour of the dots in the stackcolor:

**Example:**

## R

`# loads required package` `require` `(ggplot2)` ` ` `# sets the starting number used ` `# to generate a sequence of random ` `# numbers` `set.seed` `(0)` ` ` `# shows 100 such randomly generated` `# numbers from 10 to 50` `data <- ` `data.frame` `(x = ` `sample` `(10:50, 100, replace = ` `TRUE` `))` ` ` `# creates the stacked dot plot` `ggplot` `(data, ` `aes` `(x = x)) + ` `geom_dotplot` `()` |

**Output:**

Again, for this one too, we can make it a bit more interesting, adding some more parameters.

**Example:**

## R

`# load ggplot2` `library` `(ggplot2)` ` ` `set.seed` `(0)` `data <- ` `data.frame` `(x = ` `sample` `(0:20, 100, replace = ` `TRUE` `))` ` ` `# create customized stacked dot plot` `ggplot` `(data, ` `aes` `(x = x)) +` ` ` `geom_dotplot` `(dotsize = 1.5, stackratio = 1, ` ` ` `fill = ` `"darkgreen"` `, color = ` `"green"` `) + ` `labs` `(title = ` `"Stacked Dot Plot"` `, x = ` `"X-Axis"` `, y = ` `"Y-Axis"` `)` |

**Output:**