R – Using coord_flip() with facet_wrap(scales = “free_y”) in ggplot2 seems to give unexpected facet axis tick marks and tick labels

ggplot2r

I am trying to create a faceted plot with flipped co-ordinates where one and only one of the axes are allowed to vary for each facet:

require(ggplot2)
p <- qplot(displ, hwy, data = mpg)
p + facet_wrap(~ cyl, scales = "free_y") + coord_flip()

enter image description here

This plot is not satisfactory to me because the wrong tick marks and tick labels are repeated for each plot. I want tick marks on every horizontal axis not on every vertical axis.

This is unexpected behaviour because the plot implies that the horizontal axis tick marks are the same for the top panels as they are for the bottom ones, but they are not. To see this run:

p <- qplot(displ, hwy, data = mpg)
p + facet_wrap(~ cyl, scales = "fixed") + coord_flip()

So my question is: is there a way to remove the vertical axis tick marks for the right facets and add horizontal axis tick marks and labels to the top facets?

As Paul insightfully points out below, the example I gave can be addressed by swapping x and y in qplot() and avoiding coord_flip(), however this does not work for all geoms for example, if I want a horizontal faceted bar plot with free horizontal axes I could run:

c <- ggplot(diamonds, aes(clarity, fill=cut)) + geom_bar()
c + facet_wrap(~cut, scales = "free_y") + coord_flip()

These facets have a variable horizontal axes but repeated vertical axis tick marks instead of repeated horizontal axes tick marks. I do not think Paul's trick will work here, because unlike scatter plots, bar plots are not rotationally symmetric.

I would be very interested to hear any partial or complete solutions.

Best Answer

Using coord_flip in conjunction with facet_wrap is the problem. First you define a certain axis to be free (the x axis) and then you swap the axis, making the y axis free. Right now this is not reproduced well in ggplot2.

In your first example, I would recommend not using coord_flip, but just swapping the variables around in your call to qplot, and using free_x:

p <- qplot(hwy, displ, data = mpg)
p + facet_wrap(~ cyl, scales = "free_x")

enter image description here

Related Solutions

Rotating and spacing axis labels in ggplot2

Change the last line to

q + theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1))

By default, the axes are aligned at the center of the text, even when rotated. When you rotate +/- 90 degrees, you usually want it to be aligned at the edge instead:

alt text

The image above is from this blog post.

Java – Migration from Weblogic to Apache Tomcat

In Tomcat, these things can be defined in a couple of different places.

For the security-role re-mapping, use the standard <security-role-ref> in web.xml to re-map role names.

If you are using a servlet-3.0-spec webapp, then many of your session- and cookie-related items are available via web.xml:

<session-config>
  <cookie-config>
    <name>nameOfCookie</name>
    <max-age>-1</max-age>
  </cookie-config>
  <!-- just don't use "URL" to disable rewriting -->
  <tracking-mode>COOKIE</tracking-mode>
</session-config>

Otherwise, you'll have to resort to some acrobatics. First, I'll assume that you are using a META-INF/context.xml file within your webapp for deployment to Tomcat.

Session cookie name

<Context sessionCookieName="nameOfCookie" />

Cookie max-age
Use the standard <session-config><session-timeout /> in web.xml. (Technically, this configures the max-age of the session, but the effect is the same: the cookie will essentially become invalid after the session expires. If you really need cookie max-age, read this thread: http://markmail.org/thread/u2ysiz3uxays2w4i)
Cookie debug/tracking are not supported by configuration. You will have to write your own Filter(s) to duplicate these features.
Disabling URL rewriting will require that you write a Filter that overrides HttpServletResponse.encodeURL and HttpServletResponse.encodeRedirectURL to be no-ops on their String arguments.

Best Answer

Related Solutions

Rotating and spacing axis labels in ggplot2

Java – Migration from Weblogic to Apache Tomcat

Related Topic