---
title: |
  | STAT 408 - Week 7
  | Advanced R Graphics and ggplot2
output:
  beamer_presentation:
    theme: "PaloAlto"
    fonttheme: "structuresmallcapsserif"
date: "February 22, 2018"
---

```{r setup, include=FALSE}
library(ggplot2)
library(dplyr)
library(knitr)
knitr::opts_chunk$set(echo = TRUE)
knitr::knit_hooks$set(mysize = function(before, options, envir) {
  if (before) 
    return(options$size)
})
knitr::opts_chunk$set(fig.width=4, fig.height=3, fig.align = 'center') 
```



# Advanced R Graphics

## NCAA Basketball data
We will use data from the NCAA basketball tournament from 2011 - 2016.
```{r, mysize=TRUE, size='\\tiny'}
url <- 'http://www.math.montana.edu/ahoegh/teaching/stat408/datasets/TourneyDetailedResults.csv'
hoops <- read.csv(url,stringsAsFactors = FALSE)
hoops.2011 <- filter(hoops, Season >= 2011)
head(hoops.2011)
```

## Compute annual averages
```{r, mysize=TRUE, size='\\footnotesize'}
points <- hoops.2011 %>% 
          group_by(Season) %>% 
          summarise(Win.Points = mean(Wscore), 
                    Lose.Points = mean(Lscore),
                    Win.3Pt = mean(Wfgm3), 
                    Lose.3pt = mean(Lfgm3))
head(points)
```

## Plot types
```{r, mysize=TRUE, size='\\tiny', echo=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Lose.Points)),
     ylab='Average Points Scored', xlab='Season',
     main='Average Points Scored by Losing Teams \n in NCAA Tournament',cex.lab=.8, cex.main = .8)
```

## Plot types
```{r, mysize=TRUE, size='\\tiny', eval=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Lose.Points)),
     ylab='Average Points Scored', xlab='Season',
     main='Average Points Scored by Losing Teams \n in NCAA Tournament', cex.lab=.8, cex.main = .8)
```


## Plot types
```{r, mysize=TRUE, size='\\tiny', echo=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Lose.Points)),
     ylab='Average Points Scored', xlab='Season', type='h',lwd=3,
     main='Average Points Scored by Losing Teams \n in NCAA Tournament',cex.lab=.8, cex.main = .8)
```

## Plot types
```{r, mysize=TRUE, size='\\tiny', eval=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Lose.Points)),
     ylab='Average Points Scored', xlab='Season', type='h',lwd=3,
     main='Average Points Scored by Losing Teams \n in NCAA Tournament',cex.lab=.8, cex.main = .8)
```

## Lines
```{r, mysize=TRUE, size='\\tiny', echo=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Lose.Points)),
     ylab='Average Points Scored', xlab='Season', type='n',
     main='Average Points Scored by Losing Teams \n in NCAA Tournament',cex.lab=.8, cex.main = .8)
lines(points$Lose.Points~points$Season,col='red',lwd=1)
lines(points$Win.Points~points$Season,col='blue',lwd=1,lty=2)
```

## Lines
```{r, mysize=TRUE, size='\\tiny', eval=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Lose.Points)),
     ylab='Average Points Scored', xlab='Season', type='n',
     main='Average Points Scored by Losing Teams \n in NCAA Tournament',cex.lab=.8, cex.main = .8)
lines(points$Lose.Points~points$Season,col='red',lwd=1)
lines(points$Win.Points~points$Season,col='blue',lwd=1,lty=2)
```

## Lines and Legends
```{r, mysize=TRUE, size='\\tiny', echo=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)),
     ylab='Average Points Scored', xlab='Season', type='n',
     main='Average Points Scored in NCAA Tournament',cex.lab=.8, cex.main = .8)
lines(points$Lose.Points~points$Season,col='red',lwd=1)
lines(points$Win.Points~points$Season,col='blue',lwd=1,lty=2)
legend('bottomright',legend=c('Winning Team','Losing Team'),col=c('blue','red'),
       lwd=c(1,1), lty=c(2,1), cex = .7)
```

## Lines and Legends
```{r, mysize=TRUE, size='\\tiny', eval=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)),
     ylab='Average Points Scored', xlab='Season', type='n',
     main='Average Points Scored in NCAA Tournament',cex.lab=.8, cex.main = .8)
lines(points$Lose.Points~points$Season,col='red',lwd=1)
lines(points$Win.Points~points$Season,col='blue',lwd=1,lty=2)
legend('bottomright',legend=c('Winning Team','Losing Team'),col=c('blue','red'),
       lwd=c(1,1), lty=c(2,1), cex = .7)
```

## Points
```{r, mysize=TRUE, size='\\tiny', echo=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)),
     ylab='Average Points Scored', xlab='Season', type='l', lwd=1,col='red',
     main='Average Points Scored in NCAA Tournament',cex.lab=.8, cex.main = .8)
lines(points$Win.Points~points$Season,col='blue',lwd=1,lty=2)
points(hoops.2011$Wscore~hoops.2011$Season,pch=16,col=rgb(0,0,.5,.1))
legend('bottomright',legend=c('Average Winning Team','Average Losing Team', 'Individual Winning Team'),col=c('blue','red',rgb(0,0,.5)),
       lwd=c(1,1,NA), lty=c(2,1,NA), pch=c(NA,NA,16), cex=.7)
```

## Points
```{r, mysize=TRUE, size='\\tiny', eval=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)),
     ylab='Average Points Scored', xlab='Season', type='l', lwd=1,col='red',
     main='Average Points Scored in NCAA Tournament',cex.lab=.8, cex.main = .8)
lines(points$Win.Points~points$Season,col='blue',lwd=1,lty=2)
points(hoops.2011$Wscore~hoops.2011$Season,pch=16,col=rgb(0,0,.5,.1))
legend('bottomright',legend=c('Average Winning Team','Average Losing Team', 'Individual Winning Team'),col=c('blue','red',rgb(0,0,.5)),
       lwd=c(1,1,NA), lty=c(2,1,NA), pch=c(NA,NA,16), cex=.7)
```


## Annotation
```{r, mysize=TRUE, size='\\tiny',echo=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)),
     ylab='Average Points Scored', xlab='Season', type='l', lwd=1,col='red',
     main='Average Points Scored in NCAA Tournament',cex.lab=.8, cex.main = .8)
lines(points$Win.Points~points$Season,col='blue',lwd=1,lty=2)
points(hoops.2011$Wscore~hoops.2011$Season,pch=16,col=rgb(0,0,.5,.1))
text(2015,40,'Shot Clock Shortened', cex=.6)
arrows(x0=2015, y0=42, x1=2016, y1=70,  length=0.1, lwd=2)
legend('bottomright',legend=c('Average Winning Team','Average Losing Team', 'Individual Winning Team'),col=c('blue','red',rgb(0,0,.5)),
       lwd=c(1,1,NA), lty=c(2,1,NA), pch=c(NA,NA,16), cex=.6)
```

## Annotation
```{r, mysize=TRUE, size='\\tiny', eval=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)),
     ylab='Average Points Scored', xlab='Season', type='l', lwd=1,col='red',
     main='Average Points Scored in NCAA Tournament', cex.lab=.8, cex.main = .8)
lines(points$Win.Points~points$Season,col='blue',lwd=1,lty=2)
points(hoops.2011$Wscore~hoops.2011$Season,pch=16,col=rgb(0,0,.5,.1))
text(2015,40,'Shot Clock Shortened', cex=.6)
arrows(x0=2015, y0=42, x1=2016, y1=70,  length=0.1, lwd=2)
legend('bottomright',legend=c('Average Winning Team','Average Losing Team', 'Individual Winning Team'),col=c('blue','red',rgb(0,0,.5)),
       lwd=c(1,1,NA), lty=c(2,1,NA), pch=c(NA,NA,16), cex=.6)
```


## Axes
```{r, mysize=TRUE, size='\\tiny', echo=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)), axes=F,
     ylab='Average Points Scored', xlab='Season', type='b',pch=16, lwd=1,col='red',
     main='Average Points Scored in NCAA Tournament', cex.main=.75, cex.lab=.75)
lines(points$Win.Points~points$Season,col='blue',lwd=1,lty=2,type='b',pch=17)
legend('bottomright',legend=c('Average Winning Team','Average Losing Team'),col=c('blue','red'),
       lwd=1, lty=c(2,1),pch=c(17,16), cex=.7)
```

## Axes
```{r, mysize=TRUE, size='\\tiny', eval=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)), axes=F,
     ylab='Average Points Scored', xlab='Season', type='b',pch=16, lwd=1,col='red',
     main='Average Points Scored in NCAA Tournament', cex.main=.75, cex.lab=.75)
lines(points$Win.Points~points$Season,col='blue',lwd=1,lty=2,type='b',pch=17)
legend('bottomright',legend=c('Average Winning Team','Average Losing Team'),col=c('blue','red'),
       lwd=1, lty=c(2,1),pch=c(17,16), cex=.7)
```

## Axes
```{r, mysize=TRUE, size='\\tiny', echo=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)), axes=F,
     ylab='Average Points Scored', xlab='Season', type='b',pch=16, lwd=1,col='red',
     main='Average Points Scored in NCAA Tournament', cex.main=.75, cex.lab=.75)
lines(points$Win.Points~points$Season,col='blue',lwd=3,lty=2,type='b',pch=17)
legend('bottomleft',legend=c('Average Winning Team','Average Losing Team'),col=c('blue','red'),
       lwd=1, lty=c(2,1),pch=c(17,16), cex=.7)
axis(4)
axis(1, at = 2011:2016,labels=c('10-11','11-12','12-13','13-14','14-15','15-16'))
```

## Axes
```{r, mysize=TRUE, size='\\tiny', eval=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)), axes=F,
     ylab='Average Points Scored', xlab='Season', type='b',pch=16, lwd=1,col='red',
     main='Average Points Scored in NCAA Tournament', cex.main=.75, cex.lab=.75)
lines(points$Win.Points~points$Season,col='blue',lwd=3,lty=2,type='b',pch=17)
legend('bottomleft',legend=c('Average Winning Team','Average Losing Team'),col=c('blue','red'),
       lwd=1, lty=c(2,1),pch=c(17,16), cex=.7)
axis(4)
axis(1, at = 2011:2016,labels=c('10-11','11-12','12-13','13-14','14-15','15-16'))
```

## Axes
```{r, mysize=TRUE, size='\\tiny', echo=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)), axes=F,
     ylab='Average Points Scored', xlab='Season', type='b',pch=16, lwd=1,col='red',
     main='Average Points Scored in NCAA Tournament', cex.main=.75, cex.lab=.75)
lines(points$Win.Points~points$Season,col='blue',lwd=3,lty=2,type='b',pch=17)
legend('bottomleft',legend=c('Average Winning Team','Average Losing Team'),col=c('blue','red'),
       lwd=1, lty=c(2,1),pch=c(17,16), cex=.7)
axis(4)
axis(1, at = 2011:2016,labels=c('10-11','11-12','12-13','13-14','14-15','15-16'))
box()
```

## Axes
```{r, mysize=TRUE, size='\\tiny', eval=F}
plot(points$Lose.Points~points$Season,ylim=c(0,max(points$Win.Points)), axes=F,
     ylab='Average Points Scored', xlab='Season', type='b',pch=16, lwd=1,col='red',
     main='Average Points Scored in NCAA Tournament', cex.main=.75, cex.lab=.75)
lines(points$Win.Points~points$Season,col='blue',lwd=3,lty=2,type='b',pch=17)
legend('bottomleft',legend=c('Average Winning Team','Average Losing Team'),col=c('blue','red'),
       lwd=1, lty=c(2,1),pch=c(17,16), cex=.7)
axis(4)
axis(1, at = 2011:2016,labels=c('10-11','11-12','12-13','13-14','14-15','15-16'))
box()
```
## Superimposed Plots
```{r, echo=T, mysize=TRUE, size='\\tiny'}
plot(density(hoops.2011$Wscore),xlab='points',ylab='', main='histogram and superimposed density curve \n for points scored by winning team',lwd=3, cex.main=.8, cex.lab=.8)
hist(hoops.2011$Wscore,add=T,probability = T)
```

## Expression

```{r, echo=T, mysize=TRUE, size='\\tiny'}
plot(density(hoops.2011$Wscore),ylab=expression(beta[2]),xlab='',
     main='Examples with Expression',axes=F, type='n')
box()
text(70,.023, expression(sum(theta[i]^2, i=1, n)),cex=2)
```

## R-Markdown Captions

```{r, echo=F, mysize=TRUE, size='\\tiny',fig.align='center',fig.cap = 'Write caption here'}
plot(density(hoops.2011$Wscore),xlab='',ylab='',
     main='Captions in R Markdown',axes=F, type='n')
box()
text(70,.023, 'caption in R header',cex=1.5)
```

## Exercise: Advanced Plotting
Use the Seattle Housing Data Set [http://math.montana.edu/ahoegh/teaching/stat408/datasets/SeattleHousing.csv](http://math.montana.edu/ahoegh/teaching/stat408/datasets/SeattleHousing.csv) to create an interesting graphic, include informative titles, labels, and add an annotation.

## Solution: Advanced Plotting
```{r, echo=F,fig.align='center'}
Seattle.in <- read.csv('http://math.montana.edu/ahoegh/teaching/stat408/datasets/SeattleHousing.csv', stringsAsFactors = F)
hist(Seattle.in$price,prob=T,breaks="FD", ylab='', col='forestgreen',xlab='Sales Price (million $)', main='Houses Sold in Seattle',
     axes=F)
axis(1, at = c(0,500000,1000000,2500000,4000000,5500000,7000000), labels =c('0','.5','1','2.5','4','5.5','7'))

arrows(x0=2500000, y0=1.5e-6, x1=1500000, y1=.5e-6,  length=0.1, lwd=2)
text(2500000,1.8e-6,'Most homes sell for \n less than one million',cex=.8)
```


## Solution: Advanced Plotting
```{r, eval=F,mysize=TRUE, size='\\tiny'}
Seattle.in <- read.csv(
  'http://math.montana.edu/ahoegh/teaching/stat408/datasets/SeattleHousing.csv',
  stringsAsFactors = F)
hist(Seattle.in$price,prob=T,breaks="FD", ylab='', col='forestgreen',
     xlab='Sales Price (million $)', main='Houses Sold in Seattle', axes=F)
axis(1, at = c(0,500000,1000000,2500000,4000000,5500000,
               7000000), labels =c('0','.5','1','2.5','4','5.5','7'))

arrows(x0=2500000, y0=1.5e-6, x1=1500000, y1=.5e-6,  length=0.1, lwd=2)
text(2500000,1.8e-6,'Most homes sell for \n less than one million',cex=.8)
```

# ggplot2

## ggplot2 Overview
Why ggplot2?

### Advantages of ggplot2

- consistent underlying grammar of graphics (Wilkinson, 2005)
- plot specification at a high level of abstraction
- very flexible
- theme system for polishing plot appearance

## Grammar of Graphics
The basic idea: independently specify plot building blocks and combine them to create just about any kind of graphical display you want. 

Building blocks of a graph include:

- data
- aesthetic mapping
- geometric object
- statistical transformations
- scales
- coordinate system
- position adjustments
- faceting

## ggplot2 VS Base Graphics

Compared to base graphics, ggplot2

- is more verbose for simple / canned graphics
- is less verbose for complex / custom graphics
- does not have methods (data should always be in a data.frame)
- uses a different system for adding plot elements

## Aesthetic Mapping

Aesthetics are things that you can see. Examples include:

- position (i.e., on the x and y axes)
- color ("outside" color)
- fill ("inside" color)
- shape (of points)
- linetype
- size

Aesthetic mappings are set with the aes() function.

## Geometic Objects (geom)

Geometric objects are the actual marks we put on a plot. Examples include:

- points (`geom_point`)
- lines (`geom_line`)
- boxplot (`geom_boxplot`)

A plot must have at least one geom; there is no upper limit. You can add a geom to a plot using the + operator

## Graphical Primitives/ ggplot
```{r, mysize=TRUE, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a <- ggplot(data = hoops.2011, aes(Lfgm,Wfgm))
graph.a
```

## Adding Geoms: `geom_point()`
```{r, mysize=TRUE, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + geom_point()
```

## Adding Geoms: `geom_smooth()`
```{r, mysize=TRUE, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + geom_point() + geom_smooth(method = 'loess')
```

## Adding Geoms: `geom_rug()`
```{r, mysize=TRUE, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + geom_point() + geom_smooth(method = 'loess') + geom_rug()
```

## Adding Geoms: `geom_density2d()`
```{r, mysize=TRUE, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + geom_point() + geom_smooth(method = 'loess') + geom_rug() + geom_density2d()
```

## Adding Geoms: `geom_jitter()`
```{r, mysize=TRUE, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + geom_rug() + geom_density2d() + geom_jitter()
```

## Adding Geoms: `labs()`
```{r, mysize=TRUE, size='\\tiny',fig.align='center', fig.height=2.65}
graph.a  + geom_rug() + geom_density2d() +
 geom_jitter() + labs(x='Losing Team Field Goals Made', y = 'Winning Team Field Goals Made')
```

## Scales: `xlim()` and `ylim()`
```{r, mysize=TRUE, size='\\tiny',fig.align='center',warning=FALSE, fig.height=2.6}
graph.a + geom_rug() +   geom_density2d() +
 geom_jitter() + labs(x='Losing Team Field Goals Made', y = 'Winning Team Field Goals Made') +
  xlim(c(0,max(hoops.2011$Wfgm))) + ylim(c(0,max(hoops.2011$Wfgm)))
```

## Themes
```{r, mysize=TRUE, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + geom_point() + theme_bw() + labs(x='Losing Team Field Goals Made', y = 'Winning Team Field Goals Made')
```

## More about aes
```{r, mysize=TRUE, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + geom_jitter(col = 'firebrick4')
```

## More about aes
```{r, mysize=TRUE, eval=F, size='\\tiny',fig.align='center'}
graph.a + geom_jitter(aes(col = as.factor(Season)))
```


## More about aes
```{r, mysize=TRUE, eval=T, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + geom_jitter(aes(col = as.factor(Season)))
```

## More about aes
```{r, mysize=TRUE, eval=T, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + geom_jitter(aes(col = as.factor(Season)), size=3,alpha=.4)
```

## More about aes
```{r, mysize=TRUE, eval=T, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + geom_jitter(aes(shape = as.factor(Season),col=Wscore), size=3,alpha=.4)
```

## Faceting
```{r, mysize=TRUE, eval=F, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + facet_wrap(~Season) 
```

## Faceting
```{r, mysize=TRUE, eval=T, size='\\tiny',fig.align='center', fig.height=2.75}
graph.a + facet_wrap(~Season) + geom_jitter(alpha=.5, aes(color=Wfgm3)) 
```

## Maps
```{r, mysize=TRUE, eval=T, size='\\tiny',fig.align='center'}
library(maps)
usa <- map_data("usa")
usa.map <- ggplot() + geom_polygon(data = usa, aes(x=long, y = lat, group = group)) + 
  coord_fixed(1.3)
usa.map
```

## Maps
```{r, mysize=TRUE, eval=T, size='\\tiny',fig.align='center'}
labs <- data.frame(long = c(-111.0429, -105.2211, -80.4139, -91.7857,-121.7405),
  stringsAsFactors = FALSE,
  lat = c(45.6770, 39.7555, 37.2296,43.3033,38.5449),
  names = c("Bozeman, MT", "Golden, CO", "Blacksburg, VA",'Decorah, IA', "Davis, CA") )  
usa.map + geom_point(data = labs, aes(x = long, y = lat), color = "yellow", size = 4) +
  annotate(geom='text', y=44,x=-111,label='Bozeman,MT',col='white')
```

## More Maps: `ggmap`
```{r, mysize=TRUE, eval=T, size='\\tiny',fig.align='center'}
library(ggmap)
myMap <- get_map(location = c(lon = - 110.8281,lat = 44.4605),
                 source = "google",
                 maptype = "terrain", crop = FALSE,
                 zoom = 7)
# plot map
yellowstone.map <- ggmap(myMap)
```

## More Maps: `ggmap`
```{r, mysize=TRUE, eval=T, size='\\tiny',fig.align='center', fig.height=2.75}
yellowstone.map 
```

## Exercise: ggplot2

Now use `ggplot2` to create an interesting graph using the Seattle Housing data set.

## Solution: ggplot2
```{r,fig.align='center',echo=F}
library(ggplot2)
Seattle.in$zipcode <- as.factor(Seattle.in$zipcode)
graph.a <- ggplot(data = Seattle.in, aes(sqft_living,price))

graph.a + geom_jitter(aes(col = zipcode))+ theme(plot.title = element_text(size=8), text = element_text(size=6)) + geom_smooth(method='loess')+ggtitle('Seattle Housing Sales: Price vs. Square Footage Living Space') + ylab('Sales Price (million dollars)') + xlab('Living Space (square foot)')+scale_y_continuous(breaks=c(seq(0,7000000,by=1000000)), labels=as.character(0:7)) +  annotate('text',3500,6000000, label = 'Housing price depends on zipcode', size=2) +annotate("rect", xmin = 0, xmax = 7250, ymin = 5500000, ymax = 6500000, alpha = .6) + geom_segment(aes(x=3500, xend=3500, y=5500000, yend=3000000), 
                           arrow = arrow(length = unit(0.5, "cm"))) 
```

## Solution: ggplot2
```{r,eval=F, mysize=T, size='\\tiny'}
library(ggplot2)
Seattle.in$zipcode <- as.factor(Seattle.in$zipcode)
graph.a <- ggplot(data = Seattle.in, aes(sqft_living,price))

graph.a + geom_jitter(aes(col = zipcode)) + theme(plot.title = element_text(size=20))+
  geom_smooth(method='loess')+
  ggtitle('Seattle Housing Sales: Price vs. Square Footage Living Space') + 
  ylab('Sales Price (million dollars)') +
  xlab('Living Space (square foot)')+
  scale_y_continuous(breaks=c(seq(0,7000000,by=1000000)), labels=as.character(0:7)) +
  annotate('text',3500,6000000, label = 'Housing price depends on zipcode') +
  annotate("rect", xmin = 0, xmax = 7250, ymin = 5500000, ymax = 6500000, alpha = .6) +
  geom_segment(aes(x=3500, xend=3500, y=5500000, yend=3000000),
               arrow = arrow(length = unit(0.5, "cm"))) 
```


## Solution: map
```{r,echo=F, mysize=T, size='\\tiny', fig.align='center', fig.height=2.5}
myMap <- get_map(location = 'Seattle',
                 source = "google",
                 maptype = "terrain", crop = FALSE,
                 zoom = 8)
Seattle.map <- ggmap(myMap)
Seattle.map + geom_point(data=Seattle.in, aes(x=long, y=lat, size=price), alpha=.25) + 
  labs(title = 'Location of Housing Sales in Seattle, WA') +  theme(plot.title = element_text(size=9))
```

## Solution: map
```{r, eval=F, mysize=T, size='\\tiny', fig.height=2.5}
myMap <- get_map(location = 'Seattle',
                 source = "google",
                 maptype = "terrain", crop = FALSE,
                 zoom = 8)
Seattle.map <- ggmap(myMap)
Seattle.map + geom_point(data=Seattle.in, aes(x=long, y=lat, size=price), alpha=.25) + 
  labs(title = 'Location of Housing Sales in Seattle, WA') +  theme(plot.title = element_text(size=9))
```