r - Google Maps Platform 最多 60 个结果限制的解决方法

Question

我一直在使用 googleway 包来使用 place_type 键检索信息，但我一直坚持使用 60 results limit restriction .

我正在尝试一种稍微不同的方法来解决这个限制:分而治之。在我的工作中，所有的空间分析都是使用 QGIS 进行的，并且突然出现了一个想法。在某些坐标周围创建缓冲区；假设半径为 1 公里。然后使用该缓冲区域，我应用 hex-bin tessellation 来获取一组质心坐标，这些坐标可用于使用 60 个结果的小块来完成整个区域(1km 半径)(假设使用 googleway 包进行 100mts 半径查询)。从图形上看，直觉如所附图片所示。

为了检索 60 个结果，我使用了提供的出色解决方案 here当我执行单一搜索时，一切都很好。现在我试图通过在代码的最开头添加一个 for 循环来递归地使用一组坐标，但我不起作用。我不是一个程序员(事实上，我是一个社会学家)而且我真的不知道我做错了什么。有人能给我指出正确的方向吗？

提前致谢，危地马拉致以最诚挚的问候

这里是我的纯文本坐标文件:

coords
"14.5446147628533, -90.84266666418"
"14.5538523714673, -90.84266666418"

这里是我的代码:

###Preamble packages##
library(tidyverse)
library(googleway)
### load coordinates, plain text
dfCoords <- read.csv("~/coords.txt", sep="")
##Added For-loop begin##
for (i in dfCoords$coords) {
#### Original script begin ###
place_type <- "store" 
key <- c("API Key") 
radius <- 100 
location <- i

format_res <- function(res) {
  setNames(
    cbind(
      googleway::access_result(res, "coordinates"),
      googleway::access_result(res, "place_name")
    )
    , c("lat", "long", "name")
  )
}

do_search <- function(place_type, key, location, radius, page_token = NULL) {
  
  google_places(
    place_type = place_type,
    location = location,
    key = key,
    radius = radius,
    page_token = page_token
  )
}

full_search <- function(place_type, key, location, radius) {
  
  counter <- 0
  
  page_token <- NULL ## can start on NULL because it means we're doing the first query
  is_another_page <- TRUE 
  
  
  while( is_another_page ) {
    
    res <- do_search(place_type, key, location, radius, page_token)
    
    if( res$status == "OK" ) { ## check a valid result was returned
      
      if( counter == 0 ) {
        df <- format_res( res )
      } else {
        df <- rbind(df, format_res( res ) )
      }
      
      counter <- counter + 1
    }
    
    page_token <- res[["next_page_token"]]
    is_another_page <- !is.null( page_token )
    Sys.sleep(3)  ## Sleep the function before the next call because there's a time limit
  }
  return(df)
}

df <- full_search(place_type, key, location, radius)

##Original script ends

}
##Added for loop end

str( df )

intuition of the workaround

Answer 1

1. 您只需遍历位置并从循环内部调用函数(否则您将在每次迭代中创建和定义函数)

2. 我已将 place_id 添加到 format_res() 的结果中，因此您可以获得唯一的地点 ID。在处理结果时您将需要它，因为即使您指定了 radius，google 仍会为您提供超出此值的结果。

3. 您需要将循环的每次迭代的结果分配给一个对象。我为此创建了一个列表 lst_results

4. 您提供的两个示例坐标不会产生任何结果，因此我添加了一些错误处理以解决从 google 返回的 ZERO_RESULTS。我添加了第三个坐标对来向您展示它的工作原理。

这是完整的更新代码

library(googleway)

format_res <- function(res) {
  setNames(
    cbind(
      googleway::access_result(res, "coordinates"),
      googleway::access_result(res, "place_name"),
      googleway::access_result(res, "place")       ## store the unique place_id as well
    )
    , c("lat", "long", "name", "place_id")
  )
}

do_search <- function(place_type, key, location, radius, page_token = NULL) {
  
  google_places(
    place_type = place_type,
    location = location,
    key = key,
    radius = radius,
    page_token = page_token
  )
  
}

full_search <- function(place_type, key, location, radius) {
  
  counter <- 0
  
  page_token <- NULL ## can start on NULL because it means we're doing the first query
  is_another_page <- TRUE 
  
  ## initialise a data.frame to store the results
  df <- data.frame(
    lat = vector("numeric", 0L)
    , long = vector("numeric", 0L)
    , name = vector("character", 0L)
    , place_id = vector("character", 0L)
    )
  
  while( is_another_page ) {
    
    res <- do_search(place_type, key, location, radius, page_token)
    
    if( res$status == "OK" ) { ## check a valid result was returned
      
      if( counter == 0 ) {
        df <- format_res( res )
      } else {
        df <- rbind(df, format_res( res ) )
      }
      
      counter <- counter + 1
    } else {
      ## print a message for not-OK results
      print(paste0(res[["status"]], " for ", paste0(location, collapse = ", ") ))
    }
    
    page_token <- res[["next_page_token"]]
    is_another_page <- !is.null( page_token )
    Sys.sleep(3)  ## Sleep the function before the next call because there's a time limit
  }
  return(df)
}

## I've added a 3rd example that actually has results
dfCoords <- data.frame(
  coords = c("14.5446147628533, -90.84266666418" ,"14.5538523714673, -90.84266666418", "-37.816660, 144.967092")
)

key <- secret::get_secret("GOOGLE")
place_type <- "store" 
radius <- 100 

## create a list to store the results
lst_results <- vector("list", length = nrow(dfCoords))
## Using a list will be more efficient that `rbind`-ing a data.frame in each iteration

## loop through the indexes of the coordinates
## this wy we can assign the results to the correct index of the list
for (i in 1:nrow(dfCoords) ) {
  
  location <- dfCoords[i, "coords"]
  
  ## the coordiantes must be a numeric vector
  location <- as.numeric(strsplit(location, ",")[[1]])

  
  lst_results[[ i ]] <- full_search(
    place_type = place_type
    , key = key
    , location = location
    , radius = radius
    )
}

lapply(lst_results, head)

# [[1]]
# [1] lat  long name
# <0 rows> (or 0-length row.names)
# 
# [[2]]
# [1] lat  long name
# <0 rows> (or 0-length row.names)
# 
# [[3]]
#         lat     long                                          name                    place_id
# 1 -37.81681 144.9665           StayCentral Flinders Lane Melbourne ChIJmy5Y5YxD1moRwnnrXIAiejM
# 2 -37.81601 144.9665 EB Games / ZiNG Pop Culture - Swanston Street ChIJz6n71LVC1moR-wgn04JtBjk
# 3 -37.81666 144.9668                     Tiffany Pollard Jewellery ChIJ45afhLZC1moRnyg_JBIEf2o
# 4 -37.81666 144.9668                                 dead & buried ChIJx_udg7ZC1moR2Kw-kXTvRIw
# 5 -37.81670 144.9667                          Citizen Watch Repair ChIJtW1Cx8lC1moRxJsUpo14NAY
# 6 -37.81671 144.9669                            Paris in Melbourne ChIJR_J5hLZC1moRxZ7EIUb5ZQw