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An R package for fast web gl rendering of features on leaflet maps. It’s an R port of https://github.com/robertleeplummerjr/Leaflet.glify where more detailed information/documentation can be found. Also, if you like what you get here, make sure to star the original repo!
install.packages("leafgl")devtools::install_github("r-spatial/leafgl")It allows rendering of a large amount of features on a leaflet map. What exactly a “large amount” is, depends
Regarding 1. millions of points should be no problem, but millions of polygons might, depending on their complexity - i.e. the number of vertices.
With regard to 2., obviously the amount of RAM will matter most but there are other, more suptle, problems that can occur.
Given it’s name, leafgl is intended to fully integrate with the
leaflet package, though it is very likely that it won’t be a 1:1
replacement for the respective leaflet::add* functions. For
example, given the intention to render/visualise as many features as
possible we need to make a compromise on what additional information we
allow to be part of the rendering. So far, we allow coloring of features
and popups based on one column of the feature attributes, hence you
cannot provide your own popup content. This may seem drastic, but all
this information is costly both in terms of performance/speed and
memory. In the end, who wants to wait for a map that the browser isn’t
able to render anyway…
For starters, it doesn’t guarantee to be working tomorrow. At this
stage leafgl is pre-alpha and under heavy development so
things are likely to change frequently. For example, we are thinking
about shorter funtion names (e.g. addGlPolygons instead of
the current addGlifyPolygons). Additionally, we are still
figuring out which pathway is best to use in order to pass data from R
to the browser. As a result, rendering environments other than the
browser (or RStudio viewer) may not work properly or at all until we
approach a more stable implementation.
Depending on your operating system and browser, you may see some
weird colors that do not correspond to the ones that you specified. The
only known work-around at this stage is to set opacity = 1.
For more details the inclined reader is referred to this issue
A lot! First and foremost you can use it as often as possible and report issues/bugreports and/or feature request (see end of page for details). If you have ideas on how to enhance functionality without impacting performance too much and feel confident enough to provide pull request, please don’t hesitate. Finally, if you have proficient knowledge of JavaScript and want/know how to improve the package in any way, we would very much love to hear from you!
This will render 1 Mio. points on a standard leaflet map.
library(leaflet)
library(leafgl)
library(sf)
n = 1e6
df1 = data.frame(id = 1:n,
x = rnorm(n, 10, 3),
y = rnorm(n, 49, 1.8))
pts = st_as_sf(df1, coords = c("x", "y"), crs = 4326)
options(viewer = NULL) # view in browser
leaflet() %>%
addProviderTiles(provider = providers$CartoDB.DarkMatter) %>%
addGlPoints(data = pts, group = "pts") %>%
setView(lng = 10.5, lat = 49.5, zoom = 6)
For this we use library(colourvalues) because it can
create color voctors in the blink of an eye!
library(leaflet)
library(leafgl)
library(sf)
library(colourvalues)
n = 1e6
df1 = data.frame(id = 1:n,
x = rnorm(n, 10, 3),
y = rnorm(n, 49, 1.8))
pts = st_as_sf(df1, coords = c("x", "y"), crs = 4326)
cols = colour_values_rgb(pts$id, include_alpha = FALSE) / 255
leaflet() %>%
addProviderTiles(provider = providers$CartoDB.DarkMatter) %>%
addGlPoints(data = pts, fillColor = cols, group = "pts") %>%
setView(lng = 10.5, lat = 49.5, zoom = 6)
In reality, it only 97112 polygons… But who wants to be pedantic here?
This data was downloaded from https://download.geofabrik.de/europe/switzerland.html
library(leaflet)
library(leafgl)
library(sf)
library(colourvalues)
ch_lu = st_read("/media/timpanse/d8346522-ef28-4d63-9bf3-19fec6e13aab/bu_lenovo/software/testing/mapview/switzerland/landuse.shp")
ch_lu = ch_lu[, c(1, 3, 4)] # don't handle NAs so far
options(viewer = NULL)
cols = colour_values_rgb(ch_lu$type, include_alpha = FALSE) / 255
leaflet() %>%
addProviderTiles(provider = providers$CartoDB.DarkMatter) %>%
addGlPolygons(data = ch_lu,
color = cols,
popup = "type",
group = "pols") %>%
setView(lng = 8.3, lat = 46.85, zoom = 9) %>%
addLayersControl(overlayGroups = "pols")
Thanks to @ColinFay
leafgl has dedicated shiny functions. Given that what
leafgl produces is a leaflet map, we only need
to use leafglOutput in our ui call. In the
server call we can simply use renderLeaflet.
Here an example:
library(leaflet)
library(leafgl)
library(sf)
library(shiny)
n = 1e6
df1 = data.frame(id = 1:n,
x = rnorm(n, 10, 3),
y = rnorm(n, 49, 1.8))
pts = st_as_sf(df1, coords = c("x", "y"), crs = 4326)
options(viewer = NULL) # view in browser
m = leaflet() %>%
addProviderTiles(provider = providers$CartoDB.DarkMatter) %>%
addGlPoints(data = pts, group = "pts") %>%
setView(lng = 10.5, lat = 49.5, zoom = 4) %>%
addLayersControl(overlayGroups = "pts")
ui <- fluidPage(
leafglOutput("mymap")
)
server <- function(input, output, session) {
output$mymap <- renderLeaflet(m)
}
shinyApp(ui, server)Please file Pull requests, bug reports and feature requests at https://github.com/r-spatial/leafgl/issues
These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.