使用传单的图例

Question

我创建了这段代码，它可以工作，但是当我添加图例时，它不能很好地工作。有人可以帮助我吗？我需要图例具有与 nycounties$dimension 相同的值，我还需要重新排序增加。

    nycounties <- rgdal::readOGR("https://raw.githubusercontent.com/openpolis/geojson-italy/master/geojson/limits_IT_provinces.geojson")

city <- c("Novara", "Milano","Torino","Bari")
dimension <- as.numeric(c("1500", "5000","3000","4600"))
df <- data.frame(city, dimension)

nycounties@data = data.frame(nycounties@data,
                             df[match(nycounties@data[, "prov_name"],
                                      df[, "city"]),])
pal <- colorNumeric("viridis", NULL)

nycounties$dimension[is.na(nycounties$dimension)] = 0

leaflet(nycounties) %>%
  addTiles() %>%
  addPolygons(stroke = TRUE, smoothFactor = 0.3, fillOpacity = 1,
              fillColor = ~pal(nycounties$dimension), weight = 1, color = "black", label = nycounties$prov_name) %>%
  addLegend(pal = pal, values = ~(nycounties$dimension), opacity = 1.0,
            labFormat = labelFormat(unique(nycounties$dimension)))

Answer 1

您可以删除

labFormat = labelFormat(unique(nycounties$dimension))

并切换到

values = ~unique(dimension)

，因为您引用了错误的数据（在 nycountries 中，但必须位于 nycounties@data 中）。

因此：

leaflet(nycounties) %>%
  addTiles() %>%
  addPolygons(stroke = TRUE, smoothFactor = 0.3, fillOpacity = 1,
              fillColor = ~pal(nycounties$dimension), weight = 1, color = "black", label = nycounties$prov_name) %>%
  addLegend(pal = pal, 
            values = ~unique(dimension), 
            opacity = 1.0)

输出是：