R中自定义标记的传单图例

Question

我有一个R闪亮的应用程序，使用传单创建一个交互式地图。在此地图上，一个分类变量用于指定不同类型的点，并使用自定义标记(取决于因素级别的不同图标)可视化。

我想做的是添加一个图例到情节，但让图例显示各种标志图标，而不是坚实的颜色。传奇教程没有涵盖这一点。

我遇到了另一个所以回答这似乎解决了这个问题 --但是它是用JavaScript完成的，我不知道如何翻译它/如果它可以被翻译成在R中工作，有谁知道如何做到这一点呢？

一个可复制的基本例子：

library(leaflet)

# Sample Data
data(quakes)
quakes <- quakes[1:10,]

# Choose Icon:
leafIcons <- icons(
  iconUrl = ifelse(quakes$mag < 4.6,
                   "http://leafletjs.com/docs/images/leaf-green.png",
                   "http://leafletjs.com/docs/images/leaf-red.png"
  ),
  iconWidth = 38, iconHeight = 95,
  iconAnchorX = 22, iconAnchorY = 94)

# Produce Map:
leaflet(data = quakes) %>% addTiles() %>%
  addMarkers(~long, ~lat, icon = leafIcons)

Answer 1

虽然图标的使用是目前未执行中的addLegend()，但是益辉建议使用addControl()，使用原始的html --这是非常完美的！

library(leaflet)

# Sample Data
data(quakes)
quakes <- quakes[1:10,]

# Choose Icon:
leafIcons <- icons(
  iconUrl = ifelse(quakes$mag < 4.6,
                   "http://leafletjs.com/examples/custom-icons/leaf-green.png",
                   "http://leafletjs.com/examples/custom-icons/leaf-red.png"
  ),
  iconWidth = 38, iconHeight = 95,
  iconAnchorX = 22, iconAnchorY = 94)

html_legend <- "<img src='http://leafletjs.com/examples/custom-icons/leaf-green.png'>green<br/>
<img src='http://leafletjs.com/examples/custom-icons/leaf-red.png'>red"

# Produce Map:
leaflet(data = quakes) %>% addTiles() %>%
  addMarkers(~long, ~lat, icon = leafIcons) %>%
  addControl(html = html_legend, position = "bottomleft")

链接

• 绿色：http://leafletjs.com/examples/custom-icons/leaf-green.png
• 红色：http://leafletjs.com/examples/custom-icons/leaf-red.png
• 橙色：http://leafletjs.com/examples/custom-icons/leaf-orange.png

它产生：

​

​

Answer 2

响应上面的注释:您可以更改图例中图标的大小，而不管您定义的初始大小如何。你要做的就是添加

style='width:(desired_width)px;height:(desired_height)px';到HTML部分。

具体来说，您的代码希望：

library(leaflet)

# Sample Data
data(quakes)
quakes <- quakes[1:10,]

# Choose Icon:
leafIcons <- icons(
iconUrl = ifelse(quakes$mag < 4.6,
               "http://leafletjs.com/docs/images/leaf-green.png",
               "http://leafletjs.com/docs/images/leaf-red.png"
  ),
  iconWidth = 38, iconHeight = 95,
  iconAnchorX = 22, iconAnchorY = 94)

html_legend <- "<img src='http://leafletjs.com/docs/images/leaf-green.png'
style='width:10px;height:10px;'>green<br/> 

<img src='http://leafletjs.com/docs/images/leaf-red.png'  
style='width:10px;height:10px;'>red"

# Produce Map:
leaflet(data = quakes) %>% addTiles() %>%
addMarkers(~long, ~lat, icon = leafIcons) %>%
addControl(html = html_legend, position = "bottomleft")