title: How do I change the NA color from gray to white in a ggplot choropleth map?
body: <p>I am trying to create a choropleth map of the US that has the default color changed from gray to white.</p>
  
  <p>I have records for 18 of 48 states and the code works to color by value, but for those states where I have no records the states are gray. I would like them to be white.</p>
  
  <p>How do I change the color?</p>
  
  <pre><code>library(maps)
  library(plyr)
  library(ggplot2)
  records1&lt;-read.csv('E:/My Documents/records_by_state.csv')
  records&lt;-data.frame(state=tolower(rownames(records1)), records1)
  head(records)
  all_states&lt;-map_data("state")
  head(all_states)
  record_map&lt;-merge(all_states, records, by.x="region", by.y="state.name")
  record_map&lt;-arrange(record_map, group, order)
  head(record_map)
  
  p&lt;- ggplot()
  
  p&lt;- p + geom_polygon(data=record_map, aes(x=long, y=lat, group=group,    fill=record_map$Records), colour="black"
           )+ scale_fill_continuous(low="thistle2", high="darkred", guide="colorbar")
  P1 &lt;- p + theme_bw() +labs(fill= "Records by State"
                      , title= "By State", x="", y="")
  P1 + scale_y_continuous(breaks=c()) + scale_x_continuous(breaks=c()) +  theme(panel.border= element_blank())
  </code></pre>