Oil Spills in California by county

Here is a cool little project on mapping oil spills in California

Hello guys!

It’s been a while since I’ve last posted here, right?

This time I’ll show you some new mapping skills I learned recently thanks to Allison Horst and Casey O’Hara!

I got data on the records of California oil spills by county in 2008 from this website https://gis.data.ca.gov/datasets/7464e3d6f4924b50ad06e5a553d71086_0/data and created a few data visualizations to show exactly where oil spills occurred in an interactive map. I also created a choropleth map based on the counts of oil spills per county so we can see where they most occurred in 2008.

Here are the plots! Code is available by clicking the hide arrows.

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## Read in the data
### Oil spills by county
ca_oil_spills <- read_sf(here("data", "oil_spills", "Oil_Spill_Incident_Tracking_%5Bds394%5D.shp")) %>% 
  clean_names() %>% 
  rename(object_id = objectid,
         dfg_control = dfgcontrol,
         oes_number = oesnumber,
         date = dateofinci,
         inland_marine = inlandmari,
         time = timeofinci,
         location = specificlo,
         city = localecity,
         county_name = localecoun) 

  
### California counties shape file
ca_counties <- read_sf(here("data", "ca_counties", "CA_Counties_TIGER2016.shp")) %>% 
  clean_names() %>% 
  dplyr::select(name) %>% 
  rename(county_name = name)

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## Oil spill data wrangling
ca_oil_spills_tidy <- ca_oil_spills %>%
  mutate(date = as.Date(date)) %>% 
  mutate(date = ymd(date)) %>% 
  mutate(year = year(date)) %>% 
  dplyr::select(date, year, longitude, latitude, city, county_name, inland_marine)

Interactive map of California oil spills in 2008

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tmap_mode("view")

tm_shape(ca_counties) +
  tm_fill("county_name", palette = "Greens", title = "County") +
  tm_shape(ca_oil_spills_tidy) +
  tm_dots(size = 0.03, col = "darkorange2", border.col = "black") +
  tm_view(view.legend.position = c("right", "top"))

Figure 1: Interactive plot with the exact locations where oil spills occurred in California in 2008. You can zoom in and out of this plot and explore each county! Data source: https://gis.data.ca.gov/datasets/7464e3d6f4924b50ad06e5a553d71086_0/data

California oil spills by county

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## Part 2
## Counts of California oil spills by county
ca_oil_spills_join <- ca_counties %>% 
  st_join(ca_oil_spills_tidy)

oil_spills_count <- ca_oil_spills_join %>% 
  filter(inland_marine %in% c("Inland")) %>% 
  count(county_name.x, inland_marine) %>%
  mutate(n = as.numeric(n))


ggplot(data = oil_spills_count) +
  geom_sf(aes(fill = n),
          color = "black",
          size = 0.5) +
  scale_fill_viridis_c() +
  labs(title = "Inland oil spill records by county in California for 2008",
       fill = "Number of oil spill records") +
  theme_bw() +
  theme(axis.text = element_text(size = 10, face = "bold", color = "black"),
        panel.grid = element_blank())

Figure 2: Choropleth map of the total inland oil spills in California by county in 2008. Data source: https://gis.data.ca.gov/datasets/7464e3d6f4924b50ad06e5a553d71086_0/data