How to rearrange string X axis tick labels in ggplot2

Question

I am trying to plot trip length distribution (for every 10 miles increase in distance I want to find out the Percent of trips in that bin for that specific year). When I plot it in ggplot2 my X-axis tick labels are ordered alphabetically rather than in the order of increasing distance. I have tried using the various tricks suggested (Change the order of a discrete x scale) but am not getting anywhere. The one link My code is below and the dataset is here (http://goo.gl/W1jjfL).

library(ggplot2)
library(reshape2)

nwpt <- subset(nonwork, select=c(Distance, PersonTrips1995, PersonTrips2001, PersonTrips2009))
nwpt <- melt(nwpt, id.vars="Distance") 

ggplot(data=nwpt, aes(x=Distance, y=value, group=variable, colour=variable)) +  scale_x_discrete(name="Distance") + geom_line(size=0.5) + ggtitle("Non Work Person Trips") + ylab("Percent") 

I checked to see if the Distance variable is a factor and it is as shown below:

is.factor(nwpt$Distance) 1 TRUE

However, the output I am getting is not as I desire. Instead of Under 10 Miles being the first category, 10-14 miles being next etc. I get the plot like shown below (PDF here: http://goo.gl/V7yvxT).

Any help is appreciated. TIA Krishnan

Answer 1

Here's one way:

library(ggplot2)
library(reshape2)

nwpt <- subset(nonwork,
               select=c(DID,Distance,PersonTrips1995,PersonTrips2001,PersonTrips2009))
nwpt <- melt(nwpt, id.vars=c("DID","Distance")) 

ggplot(data=nwpt, aes(x=DID, y=value, colour=variable)) + 
  geom_line(size=0.5) + 
  labs(title="Non Work Person Trips", y="Percent") +
  scale_x_discrete(name="Distance", labels=nwpt$Distance) + 
  theme(axis.text.x=element_text(angle=90))

Produces this with your dataset: