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Mastering PCH Symbols: A Guide to Data Visualization in R

Understanding PCH in R

As one of the most widely used statistical programming languages, R has seen a lot of development over the years. The capabilities of this language are impressive, and users can efficiently carry out different data-related tasks such as visualization, analysis, and modeling.

One of the most important aspects of visualization in R is the use of symbols known as PCH. PCH is an acronym for Plot Character, and it is an important feature for data visualization in R.

This article will explore PCH in R, examining its definition, use, values, implementation, and an example of PCH in R.

Definition and Use of PCH

PCH is a symbol in R’s graphical output system which helps to enhance your plot. Plot characters are simply the explanatory symbols that are used on graphs or plots.

This character is important for recognizing different values while creating a chart. In R, PCH has various applications in data visualization.

It is mostly used as a parameter for the plotting function. The symbol is defined as an integer value and helps to interpret the data easily on the chart or plot.

The major use of PCH in R is in the enhancement of the output charts. In general, PCH can be an integer value from 0 to 25 with different shapes, and it can be an optional argument in some plotting functions.

List of PCH Symbols with Values

The aesthetic plot characters have certain shapes defined for them in R. Using these shapes can help you create an aesthetically pleasing chart.

The PCH symbols are as follows:

0 – Blank, nothing will be drawn

1 – Point (). 2 – Triangle upward (^).

3 – Triangle downward (v). 4 – Square ().

5 – Diamond (). 6 – Triangle left (<)

7 – Triangle right (>)

8 – Circle ().

9 – Bullet (). 10 – Star ().

11 – Solid Square (). 12 – Solid Circle ().

13 – Filled Triangle upward (). 14 – Filled Triangle downward ().

15 – Filled Triangle left ()

16 – Filled Triangle right ()

17 – Solid Diamond (). 18 – Solid Bullet ().

19 – Solid Star ()

20 – Solid downwards arrowhead (). 21 – Small filled square ().

22 – Small filled circle (). 23 – Solid Square () with a white cross () inside.

24 – Diamond () with a horizontal top bar. 25 – Square () with a horizontal top bar.

These symbols can be accessed by passing the integer value of the symbol as an argument to the plot function.

Implementing PCH in a Plot using Legend

Once we have the data plotted with basic features, we then focus on the formatting elements to make the chart easier to read, understand, and more visually appealing. In R, we use the ‘legend’ function to add icons that help to differentiate between various data values on a plot.

This function is used to add a legend to the plot, and it takes in argument values such as ‘x,’ ‘y,’ and ‘pch.’ Here is an example:

# Create a plot

plot(x, y, main = “Sample plot”)

# Add the legend using the legend function

legend(“topright”, legend = c(“Category A”, “Category B”, “Category C”), pch = c(1, 15, 5))

This example shows how to utilize the legend function along with PCH characters to create a more informative plot.

Creating a Data Frame for Plotting

Before you can plot a graph or chart in R, you must first create a data frame that includes the values to be plotted and any additional information required for plotting. The following code example shows how to create a data frame:

# Create a data frame

dataFrame <- data.frame(

x_axis = c(1, 2, 3, 4, 5),

y_axis = c(2, 8, 12, 18, 25),

color = c(“blue”, “green”, “red”, “orange”, “yellow”),

shape = c(4, 19, 3, 10, 11),

background = c(“gray”, “white”, “white”, “white”, “white”)


In this example, a data frame is created with a set of values for x_axis and y_axis, color and shape (using the PCH values), and background.

Plotting the Data and Adding Characteristics using PCH

Now that we have our data frame, we can create a plot and include characteristics using PCH. The following code example creates a scatter plot with our data frame and adds characteristics such as shapes and colors:

# Create a scatter plot using the data frame

plot(dataFrame$x_axis, dataFrame$y_axis, main = “Sample plot”, xlab = “X-axis”, ylab = “Y-axis”, col = dataFrame$color, pch = dataFrame$shape, bg = dataFrame$background)

As you can see, PCH is an integer value that is passed to the ‘pch’ argument in the ‘plot’ function.

PCH values determine the marker shape while ‘col’ sets the color of the marker and ‘bg’ sets the background of the marker.


In summary, PCH is a symbol used in R’s graphical output system to interpret data easily on a chart or plot. It supports the definition of several aesthetic plotting characters that allow you to create various pleasing charts.

PCH has several applications in visualizing data and is usually used in formatting elements, adding a legend, and other features to make the chart or plot more visually appealing. The use of PCH symbols is a crucial aspect of data visualization in R, and it ensures that data is presented in an intuitive way for the viewer.

In conclusion, PCH is an essential feature for data visualization in R. It uses different symbols to interpret data easily on a chart or plot and is commonly used for enhancing visual elements such as formatting and adding a legend.

The PCH symbols are vital in creating pleasing charts and are numbered from 0 to 25. We have shown how to use PCH through creating a data frame and adding characteristics with PCH.

Understanding PCH symbols is integral to creating visually appealing data visualizations in R, and this article will serve as a guide to mastering the use of PCH symbols in data visualization.

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