Create a list of icon data
An icon can be represented as a list of the form list(iconUrl,
iconSize, ...). This function is vectorized over its arguments to create a
list of icon data. Shorter argument values will be re-cycled. NULL
values for these arguments will be ignored.
icons( iconUrl = NULL, iconRetinaUrl = NULL, iconWidth = NULL, iconHeight = NULL, iconAnchorX = NULL, iconAnchorY = NULL, shadowUrl = NULL, shadowRetinaUrl = NULL, shadowWidth = NULL, shadowHeight = NULL, shadowAnchorX = NULL, shadowAnchorY = NULL, popupAnchorX = NULL, popupAnchorY = NULL, className = NULL )
iconUrl |
the URL or file path to the icon image |
iconRetinaUrl |
the URL or file path to a retina sized version of the icon image |
iconWidth, iconHeight |
size of the icon image in pixels |
iconAnchorX, iconAnchorY |
the coordinates of the "tip" of the icon
(relative to its top left corner, i.e. the top left corner means
|
shadowUrl |
the URL or file path to the icon shadow image |
shadowRetinaUrl |
the URL or file path to the retina sized version of the icon shadow image |
shadowWidth, shadowHeight |
size of the shadow image in pixels |
shadowAnchorX, shadowAnchorY |
the coordinates of the "tip" of the shadow |
popupAnchorX, popupAnchorY |
the coordinates of the point from which popups will "open", relative to the icon anchor |
className |
a custom class name to assign to both icon and shadow images |
A list of icon data that can be passed to the icon argument of
addMarkers().
library(leaflet)
# adapted from https://leafletjs.com/examples/custom-icons.html
iconData <- data.frame(
lat = c(rnorm(10, 0), rnorm(10, 1), rnorm(10, 2)),
lng = c(rnorm(10, 0), rnorm(10, 3), rnorm(10, 6)),
group = rep(sort(c("green", "red", "orange")), each = 10),
stringsAsFactors = FALSE
)
leaflet() %>% addMarkers(
data = iconData,
icon = ~ icons(
iconUrl = sprintf("https://leafletjs.com/examples/custom-icons/leaf-%s.png", group),
shadowUrl = "https://leafletjs.com/examples/custom-icons/leaf-shadow.png",
iconWidth = 38, iconHeight = 95, shadowWidth = 50, shadowHeight = 64,
iconAnchorX = 22, iconAnchorY = 94, shadowAnchorX = 4, shadowAnchorY = 62,
popupAnchorX = -3, popupAnchorY = -76
)
)
# use point symbols from base R graphics as icons
pchIcons <- function(pch = 0:14, width = 30, height = 30, ...) {
n <- length(pch)
files <- character(n)
# create a sequence of png images
for (i in seq_len(n)) {
f <- tempfile(fileext = ".png")
png(f, width = width, height = height, bg = "transparent")
par(mar = c(0, 0, 0, 0))
plot.new()
points(.5, .5, pch = pch[i], cex = min(width, height) / 8, ...)
dev.off()
files[i] <- f
}
files
}
iconData <- matrix(rnorm(500), ncol = 2)
res <- kmeans(iconData, 10)
iconData <- cbind(iconData, res$cluster)
colnames(iconData) <- c("lat", "lng", "group")
iconData <- as.data.frame(iconData)
# 10 random point shapes for the 10 clusters in iconData
shapes <- sample(0:14, 10)
iconFiles <- pchIcons(shapes, 40, 40, col = "steelblue", lwd = 2)
# note the data has 250 rows, and there are 10 icons in iconFiles; they are
# connected by the `group` variable: the i-th row of iconData uses the
# group[i]-th icon in the icon list
leaflet() %>% addMarkers(
data = iconData,
icon = ~ icons(
iconUrl = iconFiles[group],
popupAnchorX = 20, popupAnchorY = 0
),
popup = ~ sprintf(
"lat = %.4f, long = %.4f, group = %s, pch = %s", lat, lng, group, shapes[group]
)
)
unlink(iconFiles) # clean up the tmp png files that have been embeddedPlease choose more modern alternatives, such as Google Chrome or Mozilla Firefox.