Plot a legend outside of the plotting area in base graphics

Question

As the title says  How can I plot a legend outside the plotting area when using base graphics   I thought about fiddling around with layout and produce an empty plot to only contain the legend  but I would be interested in a way using just the base graph facilities and e g   par mar     to get some space on the right of the plot for the legend     Here an example   plot 1 3  rnorm 3   pch   1  lty   1  type    o   ylim c -2 2   lines 1 3  rnorm 3   pch   2  lty   2  type  o   legend 1 -1 c  group A    group B    pch   c 1 2   lty   c 1 2     produces     But as said  I would like the legend to be outside the plotting area  e g   to the right of the graph plot

User · Answer

You could do this with the Plotly R API  with either code  or from the GUI by dragging the legend where you want it   Here is an example  The graph and code are also here   x   c 0 1 2 3 4 5 6 7 8   y   c 0 3 6 4 5 2 3 5 4   x2   c 0 1 2 3 4 5 6 7 8   y2   c 0 4 7 8 3 6 3 3 4    You can position the legend outside of the graph by assigning one of the x and y values to either 100 or -100   legendstyle   list  x  100   y  1  layoutstyle   list legend legendstyle    Here are the other options    list  x    100   y    0  for Outside Right Bottom  list  x    100   y   1  Outside Right Top  list  x    100   y     5  Outside Right Middle  list  x    0   y    -100  Under Left  list  x    0 5   y    -100  Under Center  list  x    1   y    -100  Under Right    Then the response    response   p plotly x y x2 y2  kwargs list layout layoutstyle     Plotly returns a URL with your graph when you make a call  You can access that more quickly by calling browseURL response url  so it will open your graph in your browser for you   url   response url filename   response filename   That gives us this graph  You can also move the legend from within the GUI and then the graph will scale accordingly  Full disclosure  I m on the Plotly team

User · Answer

I can offer only an example of the layout solution already pointed out   layout matrix c 1 2   nrow   1   widths   c 0 7  0 3   par mar   c 5  4  4  2    0 1  plot 1 3  rnorm 3   pch   1  lty   1  type    o   ylim c -2 2   lines 1 3  rnorm 3   pch   2  lty   2  type  o   par mar   c 5  0  4  2    0 1  plot 1 3  rnorm 3   pch   1  lty   1  ylim c -2 2   type    n   axes   FALSE  ann   FALSE  legend 1  1  c  group A    group B    pch   c 1 2   lty   c 1 2

User · Answer

Adding another simple alternative that is quite elegant in my opinion   Your plot   plot 1 3  rnorm 3   pch   1  lty   1  type    o   ylim c -2 2   lines 1 3  rnorm 3   pch   2  lty   2  type  o     Legend   legend  bottomright   c  group A    group B    pch c 1 2   lty c 1 2          inset c 0 1   xpd TRUE  horiz TRUE  bty  n             Result     Here only the second line of the legend was added to your example  In turn    inset c 0 1  - moves the legend by fraction of plot region in  x y  directions  In this case the legend is at  bottomright  position  It is moved by 0 plotting regions in x direction  so stays at  right   and by 1 plotting region in y direction  from bottom to top   And it so happens that it appears right above the plot  xpd TRUE - let s the legend appear outside of plotting region  horiz TRUE - instructs to produce a horizontal legend  bty  n  - a style detail to get rid of legend bounding box    Same applies when adding legend to the side   par mar c 5 4 2 6   plot 1 3  rnorm 3   pch   1  lty   1  type    o   ylim c -2 2   lines 1 3  rnorm 3   pch   2  lty   2  type  o    legend  topleft   c  group A    group B    pch c 1 2   lty c 1 2          inset c 1 0   xpd TRUE  bty  n             Here we simply adjusted legend positions and added additional margin space to the right side of the plot  Result

User · Answer

Recently I found very easy and interesting function to print legend outside of the plot area where you want   Make the outer margin at the right side of the plot   par xpd T  mar par   mar c 0 0 0 5     Create a plot  plot 1 3  rnorm 3   pch   1  lty   1  type    o   ylim c -2 2   lines 1 3  rnorm 3   pch   2  lty   2  type  o     Add legend and just use locator 1  function as like below  Then you have to just click where you want after load following script   legend locator 1  c  group A    group B    pch   c 1 2   lty   c 1 2     Try it

User · Answer

Try layout   which I have used for this in the past by  simply creating an empty plot below  properly scaled at around 1 4 or so and placing the legend parts manually in it   There are some older questions here about legend   which should get you started

User · Answer

Sorry for resurrecting an old thread  but I was with the same problem today  The simplest way that I have found is the following     Expand right side of clipping rect to make room for the legend par xpd T  mar par   mar c 0 0 0 6      Plot graph normally plot 1 3  rnorm 3   pch   1  lty   1  type    o   ylim c -2 2   lines 1 3  rnorm 3   pch   2  lty   2  type  o      Plot legend where you want legend 3 2 1 c  group A    group B    pch   c 1 2   lty   c 1 2      Restore default clipping rect par mar c 5  4  4  2    0 1    Found here  http   www harding edu fmccown R

User · Answer

Maybe what you need is par xpd TRUE  to enable things to be drawn outside the plot region  So if you do the main plot with bty  L  you ll have some space on the right for a legend  Normally this would get clipped to the plot region  but do par xpd TRUE  and with a bit of adjustment you can get a legend as far right as it can go    set seed 1    just to get the same random numbers  par xpd FALSE    this is usually the default   plot 1 3  rnorm 3   pch   1  lty   1  type    o   ylim c -2 2   bty  L      this legend gets clipped   legend 2 8 0 c  group A    group B    pch   c 1 2   lty   c 1 2       so turn off clipping   par xpd TRUE   legend 2 8 -1 c  group A    group B    pch   c 1 2   lty   c 1 2

User · Answer

Another solution  besides the ondes already mentioned  using layout or par xpd TRUE   is to overlay your plot with a transparent plot over the entire device and then add the legend to that   The trick is to overlay a  empty  graph over the complete plotting area and adding the legend to that  We can use the par fig      option  First we instruct R to create a new plot over the entire plotting device    par fig c 0  1  0  1   oma c 0  0  0  0   mar c 0  0  0  0   new TRUE    Setting oma and mar is needed since we want to have the interior of the plot cover the entire device  new TRUE is needed to prevent R from starting a new device  We can then add the empty plot   plot 0  0  type  n   bty  n   xaxt  n   yaxt  n     And we are ready to add the legend   legend  bottomright          will add a legend to the bottom right of the device  Likewise  we can add the legend to the top or right margin  The only thing we need to ensure is that the margin of the original plot is large enough to accomodate the legend    Putting all this into a function   add legend  lt - function          opar  lt - par fig c 0  1  0  1   oma c 0  0  0  0        mar c 0  0  0  0   new TRUE    on exit par opar     plot 0  0  type  n   bty  n   xaxt  n   yaxt  n     legend          And an example  First create the plot making sure we have enough space at the bottom to add the legend   par mar   c 5  4  1 4  0 2   plot rnorm 50   rnorm 50   col c  steelblue    indianred    pch 20    Then add the legend  add legend  topright   legend c  Foo    Bar    pch 20      col c  steelblue    indianred       horiz TRUE  bty  n   cex 0 8    Resulting in

User · Answer

I like to do it like this   par oma c 0  0  0  5   plot 1 3  rnorm 3   pch 1  lty 1  type  o   ylim c -2 2   lines 1 3  rnorm 3   pch 2  lty 2  type  o   legend par  usr   2   par  usr   4   bty  n   xpd NA         c  group A    group B    pch c 1  2   lty c 1 2       The only tweaking required is in setting the right margin to be wide enough to accommodate the legend    However  this can also be automated   dev off     to reset the graphics pars to defaults par mar c par  mar   1 3   0     optional  removes extraneous right inner margin space plot new   l  lt - legend 0  0  bty  n   c  group A    group B                 plot FALSE  pch c 1  2   lty c 1  2     calculate right margin width in ndc w  lt - grconvertX l rect w  to  ndc   - grconvertX 0  to  ndc   par omd c 0  1-w  0  1   plot 1 3  rnorm 3   pch 1  lty 1  type  o   ylim c -2  2   lines 1 3  rnorm 3   pch 2  lty 2  type  o   legend par  usr   2   par  usr   4   bty  n   xpd NA         c  group A    group B    pch c 1  2   lty c 1  2

User · Answer

No one has mentioned using negative inset values for legend  Here is an example  where the legend is to the right of the plot  aligned to the top  using keyword  topright       Random data to plot  A  lt - data frame x rnorm 100  20  2   y rnorm 100  20  2   B  lt - data frame x rnorm 100  21  1   y rnorm 100  21  1      Add extra space to right of plot area  change clipping to figure par mar c 5 1  4 1  4 1  8 1   xpd TRUE     Plot both groups plot y   x  A  ylim range c A y  B y    xlim range c A x  B x    pch 1                 main  Scatter plot of two groups   points y   x  B  pch 3     Add legend to top right  outside plot region legend  topright   inset c -0 2 0   legend c  A   B    pch c 1 3   title  Group     The first value of inset c -0 2 0  might need adjusting based on the width of the legend

[r] Plot a legend outside of the plotting area in base graphics?

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