R/GoogleNearbySearch.R

In estebanlp/GoogleDataSearch: Dataframe building from Google Maps queries to allow for Spatial Economic Analysis

GoogleNearbySearch<-function(query,lat,lon,radius,apikey=NULL)
{
  requireNamespace("XML",quietly = TRUE)
  requireNamespace("RCurl",quietly = TRUE)
  query<-as.character(query)
  query<-gsub(" ","+",query)
  location<-paste0("&location=",lat,",",lon)
  radius<-paste0("&radius=",radius)
  core<-"https://maps.googleapis.com/maps/api/place/textsearch/xml?query="
  corenext<-"https://maps.googleapis.com/maps/api/place/textsearch/xml?pagetoken="
  apikey<-paste0("&key=",as.character(apikey))
  DATA<-as.data.frame(matrix(0,1,6))
  names(DATA)<-cbind("store_name","store_type","store_addr","store_lat","store_lon","store_rating")
  
  p<-1
  while(p <= 8){
  	if(p==1){
  		xml.url<-paste0(core,query,radius,location,apikey)	
  	} else {
  		xml.url <-paste0(corenext,next_page,apikey)
  	}
  
  	Sys.sleep(5)
  	xmlfile<-XML::xmlTreeParse(RCurl::getURL(xml.url))
  	xmltop <-XML::xmlRoot(xmlfile)
  	stores<-as.numeric(table(attributes(xmltop$children)$names=="result")["TRUE"])
  	n<-stores+1
  	
  	if(unclass(xmltop$children$status[[1]])[['value']]=="ZERO_RESULTS") stop("There are ZERO results for your query.")
  	if(unclass(xmltop$children$status[[1]])[['value']]=="REQUEST_DENIED") stop("Your API Key has been denied. Check your API key validity.")
  	if(unclass(xmltop$children$status[[1]])[['value']]=="INVALID_REQUEST") stop("A required parameter is missing.")
  		
  	eval(parse(text=paste0("DATA",p,"<-as.data.frame(matrix(,stores,6))")))
  	eval(parse(text=paste0("names(DATA",p,")<-c('store_name', 'store_type', 'store_addr', 'store_lat', 'store_lon', 'store_rating')")))
  
  	for(i in 1:stores){
  		store_name<-xmltop$children[2:n][[i]][['name']][[1]]
  		store_type<-xmltop$children[2:n][[i]][['type']][[1]]
  		store_addr<-xmltop$children[2:n][[i]][['formatted_address']][[1]]
  		store_lat<-xmltop$children[2:n][[i]][['geometry']][[1]][[1]][[1]]
  		store_lon<-xmltop$children[2:n][[i]][['geometry']][[1]][[2]][[1]]
  		store_rating<-xmltop$children[2:n][[i]][['rating']][[1]]
  	
  		store_name<-as.character(unclass(store_name)[['value']])
  		store_type<-as.character(unclass(store_type)[['value']])
  		store_addr <-as.character(unclass(store_addr)[['value']])
  		store_lat <-as.numeric(unclass(store_lat)[['value']])
  		store_lon <-as.numeric(unclass(store_lon)[['value']])
  		store_rating <-as.numeric(unclass(store_rating)[['value']])
  		store_rating<-ifelse(length(store_rating)==0,0,store_rating)
  		
  		eval(parse(text=paste0("DATA",p,"[(",i,"),]<-cbind(store_name,store_type,store_addr,store_lat,store_lon,store_rating)")))
  	}
  	eval(parse(text=paste0("DATA<-rbind(DATA,DATA",p,")")))
  	next_page<-unclass(xmltop$children$next_page_token[[1]])[['value']]
  	if(p>=1 & is.null(next_page)==TRUE){
  	  p<-9
  	}else {
  	  p<-p+1  
  	}
  }
  DATA<-DATA[which(DATA[,1]!=0),]
  return(DATA)
  Todelete<-as.character(ls()[grepl("DATA",ls())])
  rm(Todelete)
}