classifying circle markers by color in leaflet R and adding legend

Question

I have a data frame like c = (lat, lng, decile) which decile has ten levels. obviously, by ggmap and ggplot we can plot some points in given (lat,lng) as if we set color argument to decile column in geom_point it will classify the points and add legend automatically. But, I used leaflet to shoe the map. using this

I have written this code:

pal <- colorNumeric(
  palette = colorRampPalette(rainbow(10))(length(c$decile)), 
  domain = c$decile)

c %>% leaflet() %>% addTiles() %>% addCircleMarkers(color = ~ pal(deciles))

and I have points on my map in ten colors. so, my question has two parts: -is there a simple way like ggplot to classify colors in the leaflet? -how can I add a legend for these ten colors? in addLegend(labels , colors) how should I fix the arguments?

UPDATE: this is my c

> head(c) lat lon decile 1 35.68705 51.38176 4 2 35.80742 51.48610 6 3 35.69151 51.39816 5 4 35.66665 51.35095 2 5 35.77566 51.40209 7 6 35.70326 51.41348 8

We don't have access to `c`. Can you add it to your post? – MLavoie May 15 '18 at 16:03 — MLavoie, May 15 '18 at 16:03
I updated my question and added `c` dataframe. – mjoudy May 22 '18 at 12:35 — mjoudy, May 22 '18 at 12:35

score 2 · Answer 1 · answered Feb 25 '19 at 18:28

So I'm not totally sure I understand the question, but if I do, the gist is: you are currently using a continuous palette, but you want this to be 10 discrete categories, and you want a legend for this, is that right?

In that case can you not just use colorFactor() instead of colorNumeric()?

So like:

pal <- colorFactor(
   palette = colorRampPalette(rainbow(10))(length(c$decile)), 
   domain = c$decile)

And then

   leaflet(c) %>% 
    addTiles() %>% 
    addCircleMarkers(lng=c$lon, lat=c$lat, color = ~pal(decile)) %>% 
    addLegend("bottomright", pal = pal, values = ~decile,
            title = "Deciles")

Is that what you were after?

classifying circle markers by color in leaflet R and adding legend

1 Answers1