# Change Point Size in Graphs in R

A scatterplot is one of the most basic and popularly-used plots in R. It simply plots a point depending on the value of two variables, each at the x and the y-axis, respectively. Scatterplots can help identify any underlying pattern between these variables and show how the values are related to each other.

The following example shows a simple scatterplot graph using the `plot()`

function:

```
v1 <- c(1,2,3,4,11,9,7)
v2 <- c(3,4,5,6,3,2,1)
plot(x = v1, y = v2, xlab = "X Axis",ylab = "Y Axis",
main = "Sample Scatterplot")
```

Notice that we use the `xlab`

, `ylab`

, and `main`

parameter to add the title and labels of X and Y axes.

We can set the size and the shape of the points using the `pch`

and the `cex`

parameters.

In R, we can have different symbols for a plot. We can have a simple empty circle, square, triangle, or filled shapes, and many more. We use the `pch`

parameter to specify the shape of the point.

The `pch`

value ranges from 1 to 25, corresponding to different shapes.

In the code below, we will set the `pch`

to 20.

```
plot(x = v1, y = v2, xlab = "X Axis",ylab = "Y Axis",
main = "Sample Scatterplot", pch = 20)
```

We can use the `cex`

argument to set the size of the points to make them more readable. This parameter is generally used with the `par`

function to set other plotting parameters, but here we use it in the `plot`

function as shown below.

```
plot(x = v1, y = v2, xlab = "X Axis",ylab = "Y Axis",
main = "Sample Scatterplot", pch = 20, cex = 2)
```

Notice the difference in the graph above and how the size of the points has increased.

In case you use the `qplot()`

function to plot the scatter plot, we can set the size of the points using the `size`

parameter. See the following code.

```
qplot(v1,v2, size= I(5))
```

The same parameter can also be applied while using the `ggplot()`

function.