title: Change the shape and color of the points with ggplot
body: <p>I am new to ggplot2. I have 2 different datasets whose values has to be plotted together in a graph. Looking at example of <a href="https://stackoverflow.com/questions/15363035/ggplot2-how-to-specify-multiple-fill-colors-for-points-that-are-connected-by-li#new-answer">this question</a>  i tried using <code>scale_shape_manual()</code> and <code>scale_color_manual()</code>. But it doesn't change the shape and color of my points. </p>
  
  <p>A small part of my code is as follows:</p>
  
  <pre><code>qplot(x=TempC7, y=PresshPa7) + 
   geom_point(aes(x=Temp, y=Pres), data=obsTemp1, na.rm=TRUE) +  
   scale_shape_manual(values=c(19,19)) + 
   scale_color_manual(values=c("blue", "red"))
  </code></pre>