Plotting a custom map in shiny

I'm working on a shiny app and want to basically take a dungeon map (dungeons and dragons style, see: here for example) and add some custom points to it. Basically I was thinking of putting points on the map where someone could hover over to get more information (say "this room has 37 kindly kobolds").

I am not 100% sure what the best way to accomplish this would be. Is there a good way to load a png as a background image and overlay a scatterplot on top of it (like in plotly)?

Any help would be appreciated. Thanks

This is a first pass at a possible solution. It is slow, due to the 1 million points in the png even after I collapsed the three color values into a single number. If you hover over the dot at (300, 250) you should see the text "Here be dragons!"

PNG <- readPNG("9mYzCRX.png")
PNGbw <- apply(PNG, c(1,2), mean) #average the three colors
PNGdf <- data.frame(x = rep(1:1024, each = 1024), 
                    y = rep(1024:1, 1024),
                    Value = as.vector(PNGbw))

Comments <- data.frame(x = 300, y = 250, INFO = "Here be dragons!")
plt <- ggplot() + 
  geom_tile(data = PNGdf, mapping = aes(x = x, y = y, fill = Value)) + 
  geom_point(data = Comments, mapping = aes(x = x, y = y, text = INFO)) + 
ggplotly(plt, tooltip = "text")
1 Like

This topic was automatically closed 54 days after the last reply. New replies are no longer allowed.