Adding an overlay of plotted points to a tm_shape map created in R

Question

I create a map using the below code in R tm_shape which shades areas by number of sales (object Output_MSOA is created earlier in the code (code not shown) and takes a shape file of areas in England and joins sales by area to give all the necessary data for the mapping).

#Plot via tm_shape
OutputMap <- tm_shape(Output_MSOA) + 
  tm_fill("Incidence", style="quantile", title = "Quantiles", textNA = "0 sales", colorNA = "White", palette = "YlGnBu") +
  tm_layout(legend.position = c("left", "bottom"), 
            legend.title.size = 0.5,
            legend.text.size = 0.5,
            legend.format = list(format = "f", text.separator = "<")) +
  tm_borders(
    col = NA,
    lwd = 1,
    lty = "solid",
    alpha = NA,
    zindex = NA,
    group = NA
  ) 

I would like to add some plotted points via tm_dots as an overlay. The lat and long values of the two points are:

Warehouse	Lat	Long
One	52.625848	-0.28136
Two	52.5656	-0.23951

I gather I need to code so that tm_shape understands how to plot the lat/long values - is anyone able to help with this please? Thank you!

Answer 1

Figured it out, this works (although perhaps could be made better?)

#Create data frame of postcode long and lats
myaddresses <- data.frame(
  lat = c(52.625848, 52.5656),
  long = c(-0.28136104, -0.23951322)
)

#geocode the newly created object of addresses in usable format
geocode <- st_as_sf(myaddresses, coords = c("long", "lat"), crs = 4326)


#Create extended map with two layers
OutputMap <- tm_shape(Output_MSOA) + 
  tm_fill("Incidence", style="quantile", title = "Quantiles", textNA = "0 sales", colorNA = "White", palette = "YlGnBu") +
  tm_layout(legend.position = c("left", "bottom"), 
            legend.title.size = 0.5,
            legend.text.size = 0.5,
            legend.format = list(format = "f", text.separator = "<")) +
  tm_borders(
    col = NA,
    lwd = 1,
    lty = "solid",
    alpha = NA,
    zindex = NA,
    group = NA
  ) +
tm_shape(geocode)+
  tm_dots(col = "red", size = 0.1)


OutputMap