title: Time series and legend with ggplot2
body: <p>Thi is my data:</p>
  
  <pre><code>x &lt;- c("22-01-16","26-01-16","28-01-16","01-02-16","05-02-16","16-02-16","17-03-16","18-03-16","04-04-16","05-04-16","06-04-16","08-04-16")
  y &lt;- c(97.14,75,54.44,70.45,110.56,66.3,178.76,171.90,419.41,424,518.63,242.17)
  z &lt;- c("ADCP","ADCP","ADCP","ADCP","ADCP","ADCP","ADCP","ADCP","ADCP","ADCP","ADCP","ADCP")
  </code></pre>
  
  <p>So I make the dataframe</p>
  
  <pre><code>Datos &lt;- data.frame(x)
  Datos$Caudal &lt;- y
  Datos$Tipo &lt;- z
  Datos$Fecha &lt;- as.Date(Datos$x, "%d-%m-%y")
  </code></pre>
  
  <p>and plot using ggplot2</p>
  
  <pre><code>Serie_Caudal &lt;-
  ggplot(Datos, aes(Fecha, Caudal)) +
  geom_line(size=1, colour="red") +
  geom_point(shape=23,size=1, colour="blue",fill = "blue") +
  scale_x_date(date_breaks = "1 week",labels = date_format("%d/%b"))+
  xlab("Fecha") + ylab(bquote('Caudal ('*m^3~s^-1*')')) +
  ggtitle("Caudales Diarios (01-06/2016)")
  Serie_Caudal 
  </code></pre>
  
  <p>I try to plot a legend but i can´t the way, i try use <code>Melt</code> but my data change in a way i can´t plot. Also try <code>scale_fill_manual</code> but the legend don´t show up. I want to know if there is a way to put a legend manualy. </p>
  
  <p>The legend must show a blue point and ADCP</p>