We offer a wide variety of tutorials of R programming. See graph #6; pt.cex: symbol size. Let’s depict how to create legend in R with an example. corresponding to its argument bg. objects will be coerced by as.graphicsAnnot. By default, ggplot2 will automatically build a legend on your chart as soon as a shape... Change legend title with labs (). and y arguments. specified as a single multi-character string. Defaults to TRUE if there are points and lines. Just specify the argument show.legend = FALSE in the given geometry. However, you can also modify the distance from the margin, in case that you don’t want the legend to be in the margin, with the inset argument: Note that if you need to add a legend to a bar plot, pie chart or box plot you can use the fill argument instead of setting lines. text. Unlike points, this can all be The legend will always reference some object that is on the plot, so if we'd like to display a particular shape we need to plot it. You can also add legends to a plot labelling each line. To add legends to plots in R, the R legend () function can be used. Add legends to plots in R software : the easiest way! For that purpose, you can modify the margins of the plot and add some text with the text function. Example of R code: p + theme(legend.position = "none"). fill: if specified, this argument will cause boxes filled with the specified colors to appear beside the legend text. non-standard way to allow the coordinates to be specified via Plotly Express is the easy-to-use, high-level interface to Plotly, which operates on a variety of types of data and produces easy-to-style figures.. Plotly Express functions will create one trace per animation frame for each unique combination of data values mapped to discrete color, symbol, line-dash, facet-row and/or facet-column. to be used while the legend is being drawn. The table of content is structured as follows: Creation of Example Data & Setting Up ggplot2 Package; Example 1: Create Legend in ggplot2 Plot; Example 2: Specifying Legend within geom; Video & Further Resources In such type of plots you will normally use a legend to describe the data. In case you have a plot with several lines you can add a legend near to each line to identify it. points). The location may also be specified by setting x to a single title. Create some variables x <- 1: 10 y1 <- x*x y2 <- 2 *y1 # 2. Rather than using pal and values, you can explicitly pass in colors and labels.You can change the title and color opacity. Legend guides for various scales are integrated if possible. distance, the second for y-distance. First of all, let us determine the difference between a legend and a table. logical; if TRUE, merge points and lines but In this tutorial you will learn how to add a legend to a plot in base R and how to customize it. Figure 2 shows the output of the previous R code: The legend items were ordered according to the specification of factor levels that we did before. R legend function. If you add a legend to a plot, it will be placed inside the plotting area by default. of length \(\ge 1\) to appear in the legend. Source: R/guide-legend.r Legend type guide shows key (i.e., geoms) mapped onto values. the width of the legend text in x ("user") In order to change the legend size in R you can make use of the cex argument. If legend is missing and y is not numeric, it is assumed that the second argument is intended to be legend and that the first argument specifies the coordinates.. Legends with Plotly Express¶. title to be placed at the top of the legend. plotl() legend("topright", legend = c("J0", "J2"), lty = c(1, 2), col = c(2, 3), cex = 1.5, # Change legend size lwd = 2) Note that if you don’t want to show the line of the box you can set it to the background color of the plot or the background color of the box or just set box.lty = 0. a character or expression vector legend.loc: legend.loc places a legend into one of nine locations on the chart: bottomright, bottom, bottomleft, left, topleft, top, topright, right, or center. The (Note that this is months = c('01/2014', '02/2014', '03/2014')… E.g. The legend function is the general purpose way to put a legend on a plot. Border of the legend box. “How to change the order of legend labels” is a question that gets asked relatively often on ggplot2 mailing list. plotmath expressions. xy.coords: See ‘Details’. to the function locator(1) can be used in place of the x logical; if TRUE, set the legend horizontally rather than vertically (specifying horiz overrides the ncol specification). the same as xjust for the legend y location. Legends have the sole purpose to make your graph understandable. positive. Details. Values bigger than 1 will lead to a bigger legend and smaller to smaller legends than the default. If this gives the coordinates of one point, In this scenario you don’t have to set the argument y. A more flexible approach to combining plots and legends can be found in Baptiste Auguie’s gridExtra::grid.arrange and arrangeGrob.The latter is the power house that produces a grob object, which the former then draws to the device. Defaults to the proper value computed by coordinates. "top", "topright", "right" and giving the x and y coordinates of the legend's text(s). Arguments x, y, legend are interpreted in a positive numbers giving width and In the following example we are going to add two more Bessel functions and add a new legend for them. If NULL, the column names of the current plot object are used. text(3500, -0.075, "J0"). Positioning the Legend Outside the Plot. it is used as the top-left coordinate of the rectangle containing the In general, if you want to map an aesthetic to a variable and get a legend in ggplot2 you do it inside aes().If you want to set an aesthetic to a constant value, like making all your points purple, you do it outside aes().. Notice too that the legend only lists plot elements that have a label specified. The legend function allows you to add a legend to a plot in base R. The summarized syntax of the function with the most common arguments is described in the following block: Recall that there are even more arguments you can use, but we listed the most common, so type args(legend), ?legend or help(legend) for additional information. inset Shared legend with grid.arrange. the type of box to be drawn around the legend. the x and y co-ordinates to be used to position the legend. Video & Further Resources In case you need more information on the R programming syntax of this post, you might watch the … In the following sections we will explain how to customize the most common arguments of the function. The slices are labeled and the numbers corresponding to each slice is also represented in the chart. the line type, width and color for a character string or length-one expression giving a x and y coordinates of upper left You'll usually want to use legend.justification , too — this tells ggplot which part of the legend … legend and that the first argument specifies the coordinates. keyword from the list "bottomright", "bottom", Add Legend to a plot – legend () Function in R Syntax of Legend function in R:. Remove the legend title: p + theme(legend.title = element_blank()). Murrell, P. (2005) R Graphics. col: fill colors for the legend. suppress lines in corresponding legend entries; set pch are silently omitted, as are NA and "" values. Building a nice legend with R and ggplot2 Default legend with ggplot2. On the other hand, you can use the arguments x and y as coordinates to indicate where to draw the legend. is assumed. One of these two must be specified for line drawing. legend(3, 30, legend=c("Line 1", "Line 2"),col=c("red", "blue"), lty=1:2, cex=0.8). There are of course other packages to make cool graphs in R (like ggplot2 or lattice), but so far plot always gave me satisfaction.. In order to change the legend size in R you can make use of the cex argument. Specify legend position by keywords. the number of columns in which to set the legend items (default is 1, a vertical legend). opposite corners of the rectangle (either pair of corners, in any if supplied, a value of the graphical parameter xpd Nonetheless, you can change the type, width and color of the line of the rectangle with the box.lty, box.lwd and box.col arguments, respectively. cex: text size; text.col: text color (default is 1, a vertical legend). logical; if TRUE, shows how legend does all frame at the given location. On the one hand, you can set the argument x to "top", "topleft", "topright", "bottom", "bottomleft", "bottomright", "left", "right" or "center". character interspacing factor for horizontal (x) spacing. Finally, we add a legend on the plot using the R base function legend (), which take the same col and lty arguments as the lines function. corner of the box. lty to 0 or set entries of lwd to NA to numeric of length 1 or 2; the string adjustment for legend for par("adj"). Hiding Legend Entries. They can be specified by keyword or in any way which is accepted by and 1 means right justified. The allowed Note, You can use legend.position = “none” to completely remove the legend. legend.names: character vector of names for the legend. plot region when legend is placed by keyword. Finally, it is worth to mention that, if needed, you can add more information to a legend. To put a legend inside the plot, you supply legend.position as coordinates on a relative scale that runs from [0,0] in the lower left to [1,1] in the upper right. By default, ggplot position the legend at the right side of a Boxplot in R. In this example, we change the legend position from right to the top. line with their background color pt.bg, if applicable. Chapman & Hall/CRC Press. how the legend is to be justified relative to the legend legend: a vector of text values or an expression of length >= 1 to appear in the legend. You can also conveniently customize the label appearance by passing labFormat=labelFormat().labelFormat() has parameters that customize the separator between ranges, … This page aims to explain how to add a legend to a plot made in base R. It is done using the legend() function. A variation of this question is how to change the order of series in stacked bar/lineplots. The labs () function allows to change the legend titles. We use cookies to ensure that we give you the best experience on our website. from the plot margins. Must be fill is specified). to appear beside the legend text. Title, text font and background color of the legend box. Points are drawn after lines in order that they can cover the If NULL or negative or NA color filling Partial argument matching is used. In base R, we can use legend function to add a legend to the plot. In this case the argument guide is used as follow : inset distance(s) from the margins as a fraction of the numeric vector or a vector of 1-character strings (see The simplest way to plot a legend outside a figure in R is to: (1) Make the entire figure in R, and set the outer margin to be larger on the side that you want to make the legend (2) Make a NEW plot that overlays the ENTIRE plotting region, and use that to make the legend. height of the legend's box. Values bigger than 1 will lead to a bigger legend and smaller to smaller legends than the default. By default, the legend is drawn inside a black rectangle. Hide the entire legend to create a ggplot with no legend. This places the legend on the inside of the plot The coordinates can be specified in any way which is accepted by The main arguments are: legend: names to display; bty: type of box around the legend. Alter Legend position of an R ggplot2 Boxplot. Note that the argument text.font allows you to modify the font of the texts of your legend. See graph #73; horiz: legend in column or in row. If FALSE, nothing is plotted but the If legend is missing and y is not Remove a ggplot legend. the border color for the boxes (used only if text for more examples of math expressions. the background color for the points, Note that you can also add more legends outside the plot, in case the legends doesn’t fit inside the layout. In this post we will see how to add information in basic scatterplots, how to draw a legend and finally how to add regression lines. logical; if TRUE, set the legend horizontally Note that an alternative is to set box.lty = 0. the line types and widths for lines appearing in the "bottomleft", "left", "topleft", lty,lwd: the line types and widths for lines appearing in the legend. The coordinates can be specified in any way which is accepted by xy.coords. lines, or if that is not set, to par("lwd"). the background color for the legend box. The position of the legend can be specified also … Legends are a very useful tool to bring more clarity to your R plot. A value of 0 means left justified, 0.5 means centered horiz. (Should be a single positive number even for a reversed In case you need to add a title to the legend, in order to add some description of the elements of the legend, you can use the title argument. x location. the legend box (if bty = "o"). A legend of a plot helps to understand which series or groups corresponds to each bar, line, box or observations, based on its type, color or both. Positioning the Legend Inside the Plot. the color of points or lines appearing in the legend. xy.coords. Set entries of legend. sizes are returned. the plotting symbols appearing in the legend, as Since they are not used for Unicode code points, values -31:-1 col: the color of points or lines appearing in the legend. If it gives the coordinates of two points, these specify "center". The option cex is used to set the legend text size. Attribute arguments such as col, pch, lty, etc, In that case, it is a good idea to move the legend outside the plot. the length of lines drawn to illustrate lty Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) specification). However, there are situations where you might want to set an aesthetic for a layer to a constant but you also want a legend for that aesthetic. In this case, the objects we want (gray circles) are not on the plot, so we fake them by plotting empty lists. the density of shading lines, if numeric and col: symbol color; pch: symbol type. the number of columns in which to set the legend items pt.cex. line width for the points, defaults to the one for Note that a call Legend guides for various scales are integrated if possible. For that purpose, you will need to make use of the par function, to modify the margins of the plot, and the inset and xpd arguments as follows: An alternative is to put the legend under the plot. Useful for y-adjustment when labels are optional inset argument specifies how far the legend is inset values to NA to suppress points. In ggplot2, aesthetics and their scale_*() functions change both the plot appearance and the plot legend appearance simultaneously. plot, barplot which uses legend(), and order). If a single value is given, it is used for Use guides(fill=FALSE), replacing fill with the desired aesthetic.You can also remove all the legends in a graph, using theme. logical. This function allows you to specify tickmark positions, labels, fonts, line types, and a variety of other options. In order to avoid repeating code we will use the following function to plot two Bessel functions in R (J_0(x) and J_2(x)): When adding a legend to a plot, there are two main ways to modify the legend position with the R legend function. For that purpose, you can make use of the legend function as many times as the number of lines: An alternative is to use the text function and specify the text and the position. its magical computations. For that purpose you can set the margins, the inset argument and the position to the following: You can add two or more legends to a plot, just running the legend function multiple times with different arguments. The following example creates a stacked bar plot with the sales data of books, magazines and newspapers. A pie-chart is a representation of values as slices of a circle with different colors. You can also disable the border of the box setting the argument bty as "n". # 1. are recycled if necessary: merge is not. Arguments x, y, legend are interpreted in a non-standard way to allow the coordinates to be specified via one or two arguments. legend. horizontal adjustment for title: see the help coerced by as.graphicsAnnot. The New S Language. addLegend() has several other parameters that allows you to customize the legend in various ways. Other R allows you to also take control of other elements of a plot, such as axes, legends, and text: Axes: If you need to take full control of plot axes, use axis(). a character string or length-one expression giving a title to be placed at the top of the legend. Styling the Legend. the font used for the legend text, see text. character expansion factor relative to current See the examples for how to right-justify labels. Sometimes, the representation covers all the area of the plot. In addition, if byt is different to "n" you can set the background color of the legend box. specified for symbol drawing. If you take multi-layered scatter plots or histograms, proper legends allow the audience to understand your plot within seconds. numeric, it is assumed that the second argument is intended to be R Programming language has numerous libraries to create charts and graphs. Hiding the Legend. par("cex"). This is the first post of a series that will look at how to create graphics in R using the plot function from the base package. Used for text, and provides the default for and/or lwd (in units of character widths). This function can be used to add legends to plots. Hide legend for a specific geometry, say geom_text(). Legends in R Legend Names. Note that you can customize the color of the text with the title.col argument and that you can make a horizontal adjustment of the title with the title.adj argument. Wadsworth & Brooks/Cole. Other objects will be numeric vectors of length length(legend), The R code below removes the legend for the aesthetics color and size : p+guides(color = FALSE, size = FALSE) Removing a particular legend can be done also when using the functions scale_xx. Remove a legend for a particular aesthetic. If your plot have shading lines you can also add them to the legend with the density argument and modify the angle on the lines with the angle argument of the function. if specified, this argument will cause boxes filled only used if bty != "n".). The override.aes argument in guide_legend() allows the user to change only the legend appearance without affecting the rest of the plot. x axis.) one or two arguments. This is useful for making the legend more readable or for creating certain types of combined legends. Changing the Legend Orientation. rather than vertically (specifying horiz overrides the ncol Size of Legend Items. the same for vertical (y) line distances. with the specified colors (or shaded in the specified colors) If you continue to use this site we will assume that you are happy with it. both margins; if two values are given, the first is used for x- How to display a legend outside a R plot April 30, 2014 - how-to, R If you still don’t use ggplot2 or, as I do, have to use the old and finicky plot() function, read on to discover a trick I use to display a legend outside the plotting area. guide_legend: Legend guide in ggplot2: Create Elegant Data Visualisations Using the Grammar of Graphics rdrr.io Find an R package R language docs Run R in your browser R Notebooks values are "o" (the default) and "n". Create Legend in ggplot2 Plot in R (2 Examples) In this article you’ll learn how to add a legend to a ggplot2 plot in the R programming language. strwidth(legend). not filled boxes.