高德地图开发者文档_在 R 语言里面调用高德地图接口：地理编码与路径规划

你知道从广州南站去珠江新城怎么走么？今天就让我们一起使用 R 语言调用高德地图的地理编码(地址转经纬度)接口和路径规划接口来回答这个问题。

准备工作

注册高德地图，创建应用添加 Key(注意申请 Key 的时候服务平台应该选择“Web 服务”)。

高德地图创建应用页面链接：https://lbs.amap.com/dev/key/app
高德地图开发者文档 - 地理/逆地理编码：https://lbs.amap.com/api/webservice/guide/api/georegeo
高德地图开发者文档 - 路径规划：https://lbs.amap.com/api/webservice/guide/api/direction

从广州南站去往珠江新城

首先加载下面的操作中需要的 R 包：

library(jsonlite)
library(magrittr)
library(sf)
library(tidyverse)

设定高德地图密钥：

key "amap.key")

设定我们的起止点：

start = "广州南站"
end = "广州珠江新城"

进行路径规划前我们先要把地址转换成经纬度：

# 查询起始点的经纬度
fromJSON(paste0('https://restapi.amap.com/v3/geocode/geo?address=', start, '&key=', key)) -> start
start$geocodes$location -> start
start
#> [1] "113.267080,22.988342"

fromJSON(paste0('https://restapi.amap.com/v3/geocode/geo?address=', end, '&key=', key)) -> end
end$geocodes$location -> end
end
#> [1] "113.327343,23.119274"

下面我们进行步行规划：

route "https://restapi.amap.com/v3/direction/walking?origin=", start, "&destination=", end, "&key=", key))
# 距离
route$route$paths$distance
#> [1] "24003"

# 时间
route$route$paths$duration
#> [1] "19202"

route$route$paths$steps %>% 
  as.data.frame() %>% 
  as_tibble() -> steps
steps

#> # A tibble: 73 x 9
#>    instruction orientation road  distance duration polyline action
#>                              
#>  1 向北步行664米向右…    #>  2 沿石浦大道北步行42…    #>  3 步行24米向左前方行…    #>  4 沿石浦大道北向西北步…    #>  5 沿石洲西路向东北步行…    #>  6 步行26米右转…    #>  7 沿钟南大道步行25米…    #>  8 沿石洲西路向东北步行…    #>  9 沿石陈路向北步行27…    #> 10 沿石韦路向北步行51…    #> # … with 63 more rows, and 2 more variables: assistant_action ,#> #   walk_type 
steps %>% 
  select(polyline) %>% 
  tidytext::unnest_tokens(polyline, polyline, 
                          token = stringr::str_split, pattern = ";") %>% 
  distinct() %>% 
  separate(col = "polyline", into = c("lon", "lat"), sep = ",") %>% 
  type_convert() -> pathdf
pathdf#> # A tibble: 561 x 2#>      lon   lat#>     #>  1  113.  23.0#>  2  113.  23.0#>  3  113.  23.0#>  4  113.  23.0#>  5  113.  23.0#>  6  113.  23.0#>  7  113.  23.0#>  8  113.  23.0#>  9  113.  23.0#> 10  113.  23.0#> # … with 551 more rows
pathdf %>% 
  as.matrix() %>% 
  st_linestring() -> pathsf

最后得到的 pathsf 是个 LINESTRING，我们可以把它绘制在地图上：

library(leaflet)
library(leafem)
library(leafletCN)
leaflet(width = "100%", height = "400px") %>% 
  amap() %>% 
  addFeatures(data = pathsf, color = "red", weight = 10)

再用手机上的高德地图对比下：

是不是几乎一样哈哈！

这个地图正是使用高德地图作为地图。根据我们之前介绍的方法，我们还可以给这个地图添加标题：

# 为 leaflet 地图添加标题(这个标题在 RMarkdown 文档里似乎无法显示)
library(htmltools)
tag.map.title "
  .leaflet-control.map-title { 
    transform: translate(-50%,20%);
    position: fixed !important;
    left: 50%;
    text-align: center;
    padding-left: 10px; 
    padding-right: 10px; 
    background: rgba(255,255,255,0.75);
    font-weight: bold;
    font-size: 22px;
  }
"))
title   tag.map.title, HTML("从广州南站到珠江新城怎么走？")
)
leaflet(width = "100%", height = "400px") %>% 
  amap() %>% 
  addFeatures(data = pathsf, color = "red", weight = 10) %>% 
  addControl(title, position = "topleft", className = "map-title")

函数封装

我们可以把上面的操作封装成一个函数使用：

pathsf function(start_point = "广州南站",
                   end_point = "广州珠江新城",
                   by = "walking"){
  fromJSON(paste0('https://restapi.amap.com/v3/geocode/geo?address=', start_point, '&key=', key)) -> start
  start$geocodes$location -> start
  fromJSON(paste0('https://restapi.amap.com/v3/geocode/geo?address=', end_point, '&key=', key)) -> end
  end$geocodes$location -> end
  route "https://restapi.amap.com/v3/direction/", by, "?origin=", start, "&destination=", end, "&key=", key))
  dist   duration   route$route$paths$steps %>% 
    as.data.frame() %>% 
    as_tibble() -> steps
  steps %>% 
    select(polyline) %>% 
    tidytext::unnest_tokens(polyline, polyline, 
                            token = stringr::str_split, pattern = ";") %>% 
    distinct() %>% 
    separate(col = "polyline", into = c("lon", "lat"), sep = ",") %>% 
    type_convert() %>% 
    as.matrix() %>% 
    st_linestring() -> path
  return(list(path = path, dist = dist, duration = duration))
}

使用：

walking driving 'driving')

# 地图展示
leaflet(width = "100%", height = "400px") %>% 
  amap() %>% 
  addFeatures(data = walking$path, color = "red", weight = 10) %>% 
  addFeatures(data = driving$path, color = "green", weight = 10) %>% 
  addMouseCoordinates()

在数据框中使用

掌握如何在数据框中使用非常重要，毕竟我们接触的数据大多是表式的。我们构造一个示例数据框：

address   start = c("广州南站", "广州珠江新城", "广州海心沙亚运公园", "广州塔地铁站"),
  end = c("广州珠江新城", "广州海心沙亚运公园", "广州塔地铁站", "广州南站")
)

library(purrr)
address %>% 
  mutate(pathsf = map2(start, end, pathsf)) -> address

# 地图展示
leaflet(width = "100%", height = "400px") %>% 
  amap() %>% 
  addFeatures(data = address$pathsf[[1]]$path, color = "red", weight = 10) %>% 
  addFeatures(data = address$pathsf[[2]]$path, color = "green", weight = 10) %>% 
  addFeatures(data = address$pathsf[[3]]$path, color = "blue", weight = 10) %>% 
  addFeatures(data = address$pathsf[[4]]$path, color = "pink", weight = 10)