Introduction to amapGeocode

Geocoding and Reverse Geocoding Services are widely used to provide data about coordinate and location information, including longitude, latitude, formatted location name, administrative region with different levels. There are some package can provide geocode service such as tidygeocoder, baidumap and baidugeo. However, some of them not always provide precise information in China, and some of them is unavailable with upgrade backend API.

amapGeocode is built to provide high precise geocoding and reverse geocoding service which powered by AutoNavi Map API service. Here are two main functions to use are getCoord() which takes a character location name as an input and getLocation() which takes two numeric longitude and latitude values as inputs.

The getCoord() function extracts coordinate information from input character location name and output the result as data.table, XML or JSON (as list). And the getLocation() function extracts location information from input numeric longitude and latitude values and output the result as tibble, XML or JSON (as list). With the tibble format as output, it’s highly readable and easy to be used to tidy workflow.

Usage

Geocoding

Before start geocoding and reverse geocoding, please apply a AutoNavi Map API Key. Set amap_key globally by following command:

options(amap_key = 'REPLACE THIS BY YOUR KEY')

Then get result of geocoding, by getCoord function.

library(amapGeocode)
res <-
  getCoord('成都中医药大学')
knitr::kable(res)

The response we get from AutoNavi Map API is JSON or XML. For readability, we transform them to data.table, by setting to_table argument as TRUE by default.

If anyone want to get response as JSON or XML, just set to_table = FALSE. If anyone want to extract information from JSON or XML. The result can further be parsed by extractCoord.

res <-
  getCoord('成都中医药大学', output = 'XML',to_table = FALSE)
res

extractCoord is created to get result as a data.table.

res
tb <- 
  extractCoord(res)
knitr::kable(tb)

Reverse Geocoding

get result of reverse geocoding, by getLocation function.

res <- 
  getLocation(104.043284, 30.666864)
knitr::kable(res)

res <-
   getLocation(104.043284, 30.666864, output = 'XML',to_table = FALSE)
res

extractLocation is created to get result as a data.table.

tb <- 
  extractLocation(res)
knitr::kable(tb)

Get Subordinate Administrative Region

get result of reverse geocoding, by getAdmin function.

res <- 
  getAdmin('四川省')
knitr::kable(res)

res <-
   getAdmin('四川省', output = 'XML', to_table = FALSE)
res

extractAdmin is created to get result as a data.table.

res
tb <- 
  extractAdmin(res)
knitr::kable(tb)

Convert coordinate point from other coordinate system to AutoNavi

get result of reverse geocoding, by convertCoord function, here is how to convert coordinate from gps to AutoNavi

res <- 
  convertCoord('116.481499,39.990475',coordsys = 'gps')
knitr::kable(res)

res <-
  convertCoord('116.481499,39.990475',coordsys = 'gps', to_table = FALSE)
res

extractConvertCoord is created to get result as a data.table.

tb <- 
  extractConvertCoord(res)
knitr::kable(tb)