如何在传单中的多边形上添加标签

Question

我正在使用传单R包.我有一个由多边形组成的分区系统,我想把它们放在它们之上.下面是我的目标(与另一个软件)的说明.

谢谢你的建议!

Answer 1

由于没有可复制的数据,我决定使用我之前与传单相关的帖子之一.您希望从这篇文章中删除两件事:1)您需要创建一个包含目标区域中心点的数据框,2)您需要使用addLabelOnlyMarkers().你可以实现第一件事gCentroid().我添加了多边形数据集(UK)的行名作为字符centers.这用于标记.您需要考虑在自己的情况下使用的标签.准备好此数据集后,您需要使用它addLabelOnlyMarkers().

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)