tm_shape(bristol) + tm_fill("population", palette = "YlOrRd",
auto.palette.mapping = TRUE,
  title = "Bristol Population",
  breaks = c(0,5,10,15,20,25), colorNA = "darkgrey") + tm_borders("grey25",alpha = 0.7, lwd = 0.1) +
  tm_dots("n", size=0.1,col="green", shapeNA = NA, title = "Spaces") +
  tm_legend(text.size=1,title.size=1.2,position=c("left","top")) +
  tm_layout(legend.outside = TRUE, legend.outside.position = "bottom", title.snap.to.legend = TRUE)

tm_dots("n", size=0.1,col=Classification, shapeNA = NA, title = "Spaces")