Add Icons to Layer Control in Leaflet R

Question

how to add icons to the layer control in package Leaflet R?. I made icons with the following code:

rojos <- makeAwesomeIcon(icon='ion-waterdrop', library='ion', markerColor = 'red', iconColor = 'white')
verdes <- makeAwesomeIcon(icon='ion-waterdrop', library='ion', markerColor = 'green', iconColor = 'white')

and with the following code I made the map

agua <-leaflet(options = leafletOptions(zoomControl = TRUE,
                                        minZoom = 10, maxZoom = 17,
                                        dragging = TRUE))%>%
  addTiles()%>% 
  setView(-101.145,19.793, 10) %>%
  # MAPAS BASE
  addProviderTiles(providers$OpenStreetMap.BlackAndWhite, group = "Calles") %>%
  addProviderTiles(providers$Esri.WorldImagery, group = "Imagen satelital") %>% 
  ###########################################################################################################
addGeoJSONv2(
  jsonlite::toJSON(rojo),
  markerType="marker",
  markerIcons = rojos,
  popupProperty='popup', 
  labelProperty='NOMBRE DEL CUERPO DE AGUA',
  group = "Agua contaminada") %>%
  addGeoJSONv2(
    jsonlite::toJSON(verde),
    markerType="marker",
    markerIcons = verdes,
    popupProperty='popup', 
    labelProperty='NOMBRE DEL CUERPO DE AGUA',
    group = "Agua no contaminada") %>%
  #POLIGONOS
  addPolygons(data = cuitzeo, col="green",fillColor="Transparent", group = "Cuenca de Cuitzeo",
              weight = 3, opacity = 1)%>%
  addPolygons(data = pol_mor, col="#000000",fillColor="Transparent",  
              group = "Límite Municipal Morelia",
              weight = 2, opacity = 1, fillOpacity = .8) %>%
  # CONTROL DE CAPAS
  addLayersControl(
    baseGroups = c("Calles","Imagen satelital"),
    overlayGroups = c("Agua contaminada","Agua no contaminada","Cuenca de Cuitzeo","Límite Municipal Morelia"),
    options = layersControlOptions(collapsed = F)
  )

the result of this is the following:

I would like to get something of this style, but with my icons:

Andrew Reid · Accepted Answer · 2017-11-11T05:36:14.927

There is a relatively easy way to do this that uses the functionality of leaflet in r and doesn't rely on custom javascript controls: include html tags in your group names.

Instead of naming a group: "Group A", name it:

<div style='position: relative; display: inline-block' class='awesome-marker-icon-blue awesome-marker'>
   <i class='glyphicon glyphicon-glass icon-black '></i>
</div>
Group A

You could create this name programmatically fairly easily based on an icon name for example. Only a few things change in each name: the colors, the library (fa, ion, glyphicon), the icon class (eg: fa-glass, ion-checkmark, glyphicon-fire), and the displayed group name.

This approach creates a layer control that looks like what you want:

To make things easier, store the names in a named list/vector and use that to define the groups when appending layers and again when defining which groups should be in the control. Here's a basic example:

library(leaflet)

IconSet <- awesomeIconList(
  "Cruise Ship"   = makeAwesomeIcon(icon= 'glass', markerColor = 'blue', iconColor = 'black', library = "glyphicon"),
  "Pirate Ship" = makeAwesomeIcon(icon= 'fire', markerColor = 'black', iconColor = 'white', library = "glyphicon")
)

# Some fake data
df <- sp::SpatialPointsDataFrame(
  cbind(
    (runif(20) - .5) * 10 - 90.620130,  # lng
    (runif(20) - .5) * 3.8 + 25.638077  # lat
  ),
  data.frame(type = factor(
    ifelse(runif(20) > 0.75, "Pirate Ship", "Cruise Ship"),
    c("Cruise Ship", "Pirate Ship")
  ))
)

# group names:
groups <- c("Cruise Ship" <- "<div style='position: relative; display: inline-block' class='awesome-marker-icon-blue awesome-marker'><i class='glyphicon glyphicon-glass icon-black '></i></div>Cruise Ship",
            "Pirate Ship" <- "<div style='position: relative; display: inline-block' class='awesome-marker-icon-black awesome-marker'><i class='glyphicon glyphicon-fire icon-white '></i></div>Pirate Ship")


leaflet(df) %>% addTiles() %>%
  addAwesomeMarkers(icon = ~IconSet[type], group=~groups[type]) %>% 
  addLayersControl(                                                                                                           
    overlayGroups = groups,
    options = layersControlOptions(collapsed = FALSE)
  )

Again, if working a few layers, or dynamic layers, it shouldn't be too hard to create a function that takes the icon data and makes a corresponding name to be used later, as opposed to hard coding the names above.

Regardless, this should be usable as a way to implement icons in controls.

Is there a way to do this with custom images instead of icons? — MokeEire, Sep 19 '18 at 19:20
Yep, too late to edit but found [here](https://stackoverflow.com/questions/37701211/custom-legend-image-as-legend-in-leaflet-map) — MokeEire, Sep 19 '18 at 19:32

Add Icons to Layer Control in Leaflet R

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