Knitr and rmarkdown will not add figure captions to the output

Question

I am writing a report on Rmarkdown and knitr using RStudio, and cannot find a way to get figure captions on my document. My code for the chunk where I try to plot is like:

```{r fig1,fig.width=4,fig.height=4,echo=FALSE,message=FALSE,include=TRUE,fig.cap="Caption"}

plot(rnorm(100,2),rnorm(100,8))
```

No caption is added to the pdf output, and a look at the intermediary latex file reveals that the figure environment is not created:

\includegraphics{./Untitled_files/figure-latex/fig.pdf}

Otherwise, the pdf document is created without any problems, it just misses the captions. I have read in the knitr manual and in many other questions about the topic that the chunk option fig.cap will add the figure environment. I tried to add the fig.env=TRUE option, as well, but the results are the same. Is this an issue with rmarkdown in rstudio only or is it that in general it will not work?

Answer 1

Try adding fig_caption: yes to the YAML header of your .Rmd file. It will look something like this:

---
title: "Untitled"
author: "Nicholas"
date: "20/09/2014"
output:
  pdf_document:
    fig_caption: yes
---

There's more information here: http://rmarkdown.rstudio.com/pdf_document_format.html