CODEWITHSUNDEEP
rmapsleaflet
Heliornis
Heliornis

Reputation: 391

How to create leaflet markers colored by a numeric variable

I have a data frame with latitude, longitude, and a number. I want to add markers that are colored corresponding to these numbers. The numbers start at 1 and can be up to 100 or more.

Optimally, I would like markers with a value <= 1 to be orange, <=10 to be dark orange, <=50 to be red, and >=50 to be purple.

This seems like a simple idea, but I can't quite figure it out. I tried to use the Awesome Icons (though I would rather not) from the leaflet site (scroll down to the if statement in the Awesome Icon section), but that method was actually not working for me, and all the markers were red.

             lat            lon            number
1       19.59917     -155.42009                 3
2       22.21065     -159.47324               120
3       22.21407     -159.59058                 7
4       24.54509      -81.70717                49
5       24.54630      -81.81060                 1
6       24.55411      -81.80333                11

Above is sample data. It is part of a shiny app.

Upvotes: 4

Views: 6283

Answers (1)

jazzurro
jazzurro

Reputation: 23574

Since there is no reproducible data, I created a sample data. First, I obtained polygon data for California and created random data points staying in California. Then, I added random numbers staying between 0 and 100. Then, I created a grouping variable called group, which is for coloring in icons. You want dark orange. But, seeing the CRAN manual, the color is not available for makeAwesomeIcon(). So I chose dark red, instead. Then, I created icons and drew a map. Since there is no reproducible data, I cannot see what you have in your hand. But I hope this demonstration gets you going.

library(raster)
library(sp)
library(dplyr)
library(leaflet)

usa <- getData("GADM", country = "usa", level = 1)
cal <- subset(usa, NAME_1 == "California")

foo <- as(cal, "SpatialPolygons")

set.seed(111)
mydata <- spsample(foo, n = 100, "random") %>%
          as.data.frame %>%
          mutate(number = sample.int(n = 100, replace = FALSE),
                 group = cut(number, breaks = c(0, 1, 10, 50, Inf),
                             labels = c("orange", "darkred", "red", "purple"),
                 include.lowest = TRUE)) %>%
          rename(long = x, lat = y)

icons <- awesomeIcons(icon = "whatever",
                      iconColor = "black",
                      library = "ion",
                      markerColor = mydata$group)

leaflet() %>%
addProviderTiles("OpenStreetMap.Mapnik") %>%
addAwesomeMarkers(data = mydata, ~long, ~lat, icon = icons)

enter image description here

Upvotes: 6

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