Popup when hover with leaflet in R? - r

Question

My leaflet map looks something like this:
library(sp)
library(leaflet)
circleFun <- function(center = c(0,0),diameter = 1, npoints = 100){
r = diameter / 2
tt <- seq(0,2*pi,length.out = npoints)
xx <- center[1] + r * cos(tt)
yy <- center[2] + r * sin(tt)
Sr1 = Polygon(cbind(xx, yy))
Srs1 = Polygons(list(Sr1), "s1")
SpP = SpatialPolygons(list(Srs1), 1:1)
return(SpP)
}
Circle.Town <- circleFun(c(1,-1),2.3,npoints = 100)
df1 <- data.frame(long=c(0.6,1,1.4), lat=c(-2, -.8, -0.2), other=c('a', 'b', 'c'), VAM=c(10,8,6),
type=c('Public', 'Public', 'Private'), id=c(1:3)) %>%
mutate(X=paste0('<strong>id: </strong>',
id,
'<br><strong>type</strong>: ',
type,
'<br><strong>VAM</strong>: ',
VAM))
# Create a continuous palette function
pal <- colorNumeric(
palette = "RdYlBu",
domain = df1$VAM
)
leaflet(height = "400px") %>%
addTiles() %>%
addPolygons(data = Circle.Town, color = 'green', fillOpacity = .7) %>%
addCircleMarkers(data = df1, lat = ~lat, lng =~long,
radius = ~VAM, popup = ~as.character(X),
fillColor = ~pal(VAM),
stroke = FALSE, fillOpacity = 0.8,
clusterOptions = markerClusterOptions()) %>%
addLegend(position = "topright",
pal = pal, values = df1$VAM,
title = "VAM",
opacity = 1
) %>%
setView(lng = 1, lat = -1, zoom = 8)
Right now, I get a popup when I click one of the circles. Is it possible to get the information when I hover the mouse instead of click? Ideally, I would like something like this.
Thanks!

Answer 1

This may have been added to the leaflet package since this question was posed a year ago, but this can be done via the label argument. I am using leaflet R package version 1.1.0.
Read the data in as above:
library(sp)
library(leaflet)
library(dplyr)
circleFun <- function(center = c(0,0),diameter = 1, npoints = 100){
r = diameter / 2
tt <- seq(0,2*pi,length.out = npoints)
xx <- center[1] + r * cos(tt)
yy <- center[2] + r * sin(tt)
Sr1 = Polygon(cbind(xx, yy))
Srs1 = Polygons(list(Sr1), "s1")
SpP = SpatialPolygons(list(Srs1), 1:1)
return(SpP)
}
Circle.Town <- circleFun(c(1,-1),2.3,npoints = 100)
df1 <- data.frame(long=c(0.6,1,1.4), lat=c(-2, -.8, -0.2), other=c('a', 'b', 'c'), VAM=c(10,8,6),
type=c('Public', 'Public', 'Private'), id=c(1:3)) %>%
mutate(X=paste0('<strong>id: </strong>',
id,
'<br><strong>type</strong>: ',
type,
'<br><strong>VAM</strong>: ',
VAM))
# Create a continuous palette function
pal <- colorNumeric(
palette = "RdYlBu",
domain = df1$VAM
)
But create a list of labels instead of vector:
labs <- as.list(df1$X)
And then lapply the HTML function over that list within the label argument. Note to use label instead of popup.
library(htmltools)
leaflet(height = "400px") %>%
addTiles() %>%
addPolygons(data = Circle.Town, color = 'green', fillOpacity = .7) %>%
addCircleMarkers(data = df1, lat = ~lat, lng =~long,
radius = ~VAM, label = lapply(labs, HTML),
fillColor = ~pal(VAM),
stroke = FALSE, fillOpacity = 0.8,
clusterOptions = markerClusterOptions()) %>%
addLegend(position = "topright",
pal = pal, values = df1$VAM,
title = "VAM",
opacity = 1
) %>%
setView(lng = 1, lat = -1, zoom = 8)
This method is described in an an answer to this SO question: R and Leaflet: How to arrange label text across multiple lines
There is more info on HTML in labels in leaflet documentation:
https://rstudio.github.io/leaflet/popups.html

Answer 2

Here is an alternative:
library(leaflet)
library(htmltools)
library(htmlwidgets)
yourmap <- leaflet(height = "400px") %>%
addTiles() %>%
addPolygons(data = Circle.Town, color = 'green', fillOpacity = .7) %>%
addCircleMarkers(data = df1, lat = ~lat, lng =~long,
radius = ~VAM, popup = ~as.character(X),
fillColor = ~pal(VAM),
stroke = FALSE, fillOpacity = 0.8,
clusterOptions = markerClusterOptions()) %>%
addLegend(position = "topright",
pal = pal, values = df1$VAM,
title = "VAM",
opacity = 1
) %>%
setView(lng = 1, lat = -1, zoom = 8)
setwd("~/Desktop/")
saveWidget(yourmap, file="yourmap.html")
In your desktop, you will have an html and a folder saved under yourmap. Open the leaflet.js file located in /pathTo/yourmap_files/leaflet-binding-1.0.1.9002.
In leaflet.js, scroll down to var popup = df.get(i, 'popup');
and paste just below:
marker.on('mouseover', function (e) {
this.openPopup();
});
marker.on('mouseout', function (e) {
this.closePopup();
});
Save and reopen yourmap.html file. Hover on one of your point!!