由于没有可重复使用的数据,我决定使用我之前发布的与leaflet相关的帖子之一。从这篇文章中,您需要了解两件事:1)您需要创建一个包含目标区域中心点的数据框架,2)您需要使用addLabelOnlyMarkers()
。您可以使用gCentroid()
来实现第一件事。我将多边形数据集(英国)的行名称添加为字符到centers
中。这用于标记。您需要考虑在自己的情况下使用哪些标签。一旦准备好此数据集,您就需要在addLabelOnlyMarkers()
中使用它。
library(raster)
library(rgeos)
library(leaflet)
# Get UK polygon data
UK <- getData("GADM", country = "GB", level = 2)
# Find a center point for each region
centers <- data.frame(gCentroid(UK, byid = TRUE))
centers$region <- row.names(UK)
### Create dummy data
set.seed(111)
mydf <- data.frame(place = unique(UK$NAME_2),
value = sample.int(n = 1000, size = n_distinct(UK$NAME_2), replace = TRUE))
### Create five colors for fill
mypal <- colorQuantile(palette = "RdYlBu", domain = mydf$value, n = 5, reverse = TRUE)
leaflet() %>%
addProviderTiles("OpenStreetMap.Mapnik") %>%
setView(lat = 55, lng = -3, zoom = 6) %>%
addPolygons(data = UK,
stroke = FALSE, smoothFactor = 0.2, fillOpacity = 0.3,
fillColor = ~mypal(mydf$value),
popup = paste("Region: ", UK$NAME_2, "<br>",
"Value: ", mydf$value, "<br>")) %>%
addLabelOnlyMarkers(data = centers,
lng = ~x, lat = ~y, label = ~region,
labelOptions = labelOptions(noHide = TRUE, direction = 'top', textOnly = TRUE)) %>%
addLegend(position = "bottomright", pal = mypal, values = mydf$value,
title = "UK value",
opacity = 0.3)