plotAll-ig-van-2015-pointsize1.0.alpha0.4.R

library(ggmap)
data4 = read.csv(file="/Users/rtanglao/Dropbox/GIT/rtgram/10March2016-instagram-vancouver-top-colour-lat-long-2015.csv", stringsAsFactors=F)

# following theme is from:
# http://stackoverflow.com/questions/6736378/how-do-i-change-the-background-color-of-a-plot-made-with-ggplot2
theme_map <- function (base_size = 12, base_family = "") {
  theme_gray(base_size = base_size, base_family = base_family) %+replace% 
    theme(
      axis.line=element_blank(),
      axis.text.x=element_blank(),
      axis.text.y=element_blank(),
      axis.ticks=element_blank(),
      axis.ticks.length=unit(0.3, "lines"),
      axis.text = element_text(margin=unit(0.5, "lines")),
      axis.title.x=element_blank(),
      axis.title.y=element_blank(),
      legend.background=element_rect(fill="white", colour=NA),
      legend.key=element_rect(colour="white"),
      legend.key.size=unit(1.2, "lines"),
      legend.position="right",
      legend.text=element_text(size=rel(0.8)),
      legend.title=element_text(size=rel(0.8), face="bold", hjust=0),
      panel.background=element_blank(),
      panel.border=element_blank(),
      panel.grid.major=element_blank(),
      panel.grid.minor=element_blank(),
      panel.margin=unit(0, "lines"),
      plot.background=element_blank(),
      plot.margin=unit(c(1, 1, 0.5, 0.5), "lines"),
      plot.title=element_text(size=rel(1.2)),
      strip.background=element_rect(fill="grey90", colour="grey50"),
      strip.text.x=element_text(size=rel(0.8)),
      strip.text.y=element_text(size=rel(0.8), angle=-90) 
    )   
}
(p <- qplot(long, lat, geom = "point", data = data4, color=I(data4$color), xlim=c(-123.27, -123.005), ylim=c(49.21, 49.324), size=I(1.0), alpha=I(0.4)) + theme_map())