This R script downloads King County WA parcel open data in R as an sf object, and creates point-based centroids for each_parcel.

King_County_Parcel_getting_started.R

#This R script downloads King County WA parcel open data in R as an sf object, and creates point-based centroids for each_parcel.
#This script is intented to help you get up and running. 

#Tempfile used for downloading.
temp <- tempfile()
temp2 <- tempfile()
#Download the open data ArcGIS zip folder containing the parcel data as a .shp file.  
# As an alternative, you can download KML or csv version from here: https://gis-kingcounty.opendata.arcgis.com/datasets/parcels-for-king-county-with-address-with-property-information-parcel-address-area
download.file("https://opendata.arcgis.com/datasets/c7a17b7ad3ec44b7ae64796dca691d72_1722.zip",temp)
#Unzip the contents of 'temp' object and save unzipped content in 'temp2'
unzip(zipfile = temp, exdir = temp2)
#Finds the filepath of the shapefile (.shp) file in the temp2 unzip folder.
#the $ at the end of ".shp$" ensures you are not also finding files such as .shp.xml 
your_SHP_file<-list.files(temp2, pattern = ".shp$",full.names=TRUE)
#Read the shapefile.
library(sf)
library(ggplot2)
KC<- sf::st_read(your_SHP_file)
#Create usable centroid points for each parcel
  KC$centroids<-st_transform(KC, 4326) %>% st_centroid(KC) %>% st_geometry()
  KC$long<-st_coordinates(KC$centroids)[,1]
  KC$lat<-st_coordinates(KC$centroids)[,2]
  head(KC$centroids)
   
#Make a basic ggplot of all KC parcels.
#NOTE: Try subsetting to something specific for faster load, since this could take minutes.
p<- ggplot() +  geom_sf(data=KC,aes(fill=APPR_IMPR))+
  scale_fill_gradient(low = "#FFFFE0", high = "#6f42c1")+
   geom_sf(data = KC$centroids, size = 1, shape = 21, fill = "#0061AC") + 
  coord_sf(xlim =c(-122.45,  -122.0), ylim = c(47.4,47.77), expand = FALSE,crs = st_crs(4326))

#Add labels and view.
p+ theme_bw() +labs(title="King Count Parcel Data", subtitle="What will you uncover?", x="", y="")
#Start your exploratory data analysis