sf plots with ggplot
You may also be familiar with the ggplot2 library, where a ggplot plot is made of several layers.
It turns out that sf objects can also be plotted using the ggplot2 library. As a quick revision, recall that the first layer is a blank canvas that's created by ggplot(). Subsequent layers are placed on top of each other by adding geom functions (which take the form geom_<plot>), labs(), themes and the like.
In the following, you will build a ggplot map using several sf objects.
The listings dataframe, a multipolygon called london_poly, and a collection of points called num_listings have also been loaded. The tidyverse and sf libraries have already been imported.
Este exercício faz parte do curso
Building Dashboards with shinydashboard
Instruções do exercício
- Set the coordinates reference system (CRS) of
num_listingsto that oflondon_poly. - Add the multipolygon to the blank canvas.
- Set the
fillargument such that each neighborhood, as seen in theNameattribute, has a different fill. - Add a label at the center of each polygon.
Exercício interativo prático
Experimente este exercício completando este código de exemplo.
# Set the CRS of num_listings to that of london_poly
st_crs(num_listings) <- ___(___)
# Add the multipolygon to the blank canvas
___ +
# Set a different fill for each neighborhood
geom_sf(aes(___)) +
# Add a label at the center of each polygon
___(data=num_listings, aes(label=`Number of listings`)) +
theme_classic()