Tidying up the legend and some final tweaks
Time for some final tweaks and then to save your plot.
Every element in your plot is a target for tweaks. Is it the right color? Is it the right size? Does it have intuitive labels? Your goal is to emphasize the data and de-emphasise the non-data elements.
We've got some ideas for this plot. Let's tweak a few things.
This exercise is part of the course
Visualizing Geospatial Data in R
Exercise instructions
- Make it clear what the color represents by adding
title = "Median Income"
andpalette = "Greens"
in thetm_fill()
call, which will map income to a green color scale. - Add subtle borders to the tracts to make it more clear where their boundaries are by adding a
tm_borders()
layer withcol = "grey60"
andlwd = 0.5
. - Make the neighborhood boundaries a little more important than tract boundaries by setting
col = "grey40"
andlwd = 2
. - Add a data source credit using a
tm_credits()
call with first argument"Source: ACS 2014 5-year Estimates, \n accessed via acs package"
and second argumentposition = c("right", "bottom")
. - Finally, save your plot as
"nyc_income_map.png"
using thetmap_save()
function with argumentswidth = 4
andheight = 7
.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
library(tmap)
tm_shape(nyc_tracts_merge) +
# Add title and change palette
tm_fill(col = "estimate",
___,
___) +
# Add tm_borders()
___ +
tm_shape(water) +
tm_fill(col = "grey90") +
tm_shape(manhat_hoods) +
# Change col and lwd of neighborhood boundaries
tm_borders() +
tm_text(text = "name", size = 0.5) +
# Add tm_credits()
# Save map as "nyc_income_map.png"