6 Challenges

Let us move to the challenge part of the seminar to examine your understanding. Below are two graphs created by ggplot() based on housedata2.

6.1 Challenge 1: reorder the items in legend

ggplot(data=housedata2, aes(x= yearchi, y=priceper,group=region,color=region)) +geom_point(size=2)+
  geom_line(size = 1)+
  theme_bw()+
  theme(axis.title = element_text(size=15), axis.text = element_text(size=13),strip.text = element_text(size=15),legend.text = element_text(size=11),legend.title = element_text(size=13))+
  ylab(bquote("House price ( £/"~m^2 ~ ")"))+xlab("Year")+
  guides(color=guide_legend("Region")) +
  scale_y_continuous(labels = scales::comma,)+scale_x_continuous(breaks = c(2009,2010,2011,2012,2013,2014,2015,2016))

6.2 Challenge 2: Manualy setting the colour of the line and point

# calculate the rank order of house price in each region at each transaction year.
result1 <- data.frame()
ms <- 0
autodata <-0
j <- 1
list <-unique(housedata2$yearchi)
for(ms in list)
{
  print(ms)
  print(j)
  autodata <- housedata2[housedata2$yearchi==ms,]
  autodata$ranknew <- rank(-autodata$priceper)
  autodata$ranknew1 <- rank(autodata$priceper)
  result1 <- rbind(result1,autodata)
  j <- j+1
  
}

## [1] 2009
## [1] 1
## [1] 2012
## [1] 2
## [1] 2015
## [1] 3
## [1] 2016
## [1] 4
## [1] 2011
## [1] 5
## [1] 2014
## [1] 6
## [1] 2010
## [1] 7
## [1] 2013
## [1] 8

head(result1)

##          gor yearchi priceper                   region ranknew ranknew1
## 1  E12000001    2009 1425.943               North East       9        1
## 13 E12000002    2009 1554.641               North West       7        3
## 24 E12000003    2009 1585.518 Yorkshire and The Humber       6        4
## 32 E12000004    2009 1528.438            East Midlands       8        2
## 35 E12000005    2009 1686.191            West Midlands       5        5
## 44 E12000006    2009 2104.026          East of England       3        7

# Plot house price rank order change between 2009 and 2016

ggplot(data=result1,aes(x=yearchi, y=ranknew,group=region,color=region))+
  geom_line(aes(color = region, alpha = 1), size = 0.7) +
  geom_point(data = result1[(result1$yearchi == "2009"|result1$yearchi == "2016"),],
             aes(x=yearchi, y=ranknew,group=region,color = region),
             size = 8)+
  geom_text(data = result1[result1$yearchi == "2016",], 
            aes(label = region) , 
            position = position_nudge(x = 0.4),
            hjust = 0,
            size = 5) +
  geom_label(data = result1[(result1$yearchi == "2009"|result1$yearchi == "2016"),],
             aes(label = ranknew), 
             color="white",
             alpha = 0,
             size = 5,
             label.padding = unit(0.00, "lines"), 
             label.size = 0.0)+
  theme_bw()+ scale_x_continuous(limits = c(2007, 2021),breaks = c(2009,2010,2011,2012,2013,2014,2015,2016))+
  scale_y_reverse( breaks = unique(result1$ranknew))+
  theme(legend.position = "none",axis.text = element_text(size=13))+
  theme(axis.line=element_blank(),
      axis.text.y=element_blank(),
      axis.ticks=element_blank(),
      axis.title.x=element_blank(),
      axis.title.y=element_blank(),
      panel.background=element_blank(),
      panel.border=element_blank(),
      panel.grid.major.y = element_blank(),
      panel.grid.minor.x=element_blank(),
      panel.grid.minor.y=element_blank(),
      plot.background=element_blank())