Travel Distance Matrix Data Function for Spotfire

Introduction

This data function is a geospatial function to calculate the driving distances between a single point on Earth to all points in a data table. Latitude and longitude data must be provided for the originating point, as well as the destination points in the data table.

The data function provides travel time and travel distance based on transportation infrastructures such as roads and ferries and is not a simple distance calculation as the crow flies. The user needs to have access to Spotfire Geoanalytics Builder REST API Service and Spotfire either through trial or license.

Data Function

# [TERR] Driving Distance Matrix
# Neil Kanungo, 2020
# TIBCO Software

# Description:
#   Get the driving distance and times from the central lat/long point to all points
#   in another data table

# Inputs:
#   start.lon - Longitude column of the Trade Area Center data table
#   start.lat - Latitude column of the Trade Area Center data table
#   destinations.df - Data Table with all hospital info

# Outputs:
#   output.df - Distance matrix data from Trade Area Center to all hospitals within it


#----------------------------------------------

# Load libraries
suppressMessages(suppressWarnings(library(jsonlite,warn.conflicts=FALSE,quietly=TRUE)))

# Set API Key (password) for running this data function with TIBCO Geoanalytics Builder
api.key <-"ENTER YOUR API KEY HERE" #contact Arnaud Varin (avarin@tibco.com) for a key

# Build Destination lat/long table
destinations.df <- cbind(destinations.lon, destinations.lat)

# Get starting coords
start.lon <- round(start.lon[1],2)
start.lat <- round(start.lat[1],2)

# Create null Segments Data Frame
mySegments <- data.frame(
  Number=integer(),
  StartName=character(),
  EndName=character(),
  DrivingDistance.Km=character(),
  DrivingDistance.Meters=integer(),
  DrivingDistance.Miles=character(),
  DrivingDistance.Feet=integer(),
  DrivingTime.hh_mm=character(),
  DrivingTime.seconds=integer(),
  StartLocation.Latitude=double(),
  StartLocation.Longitude=double(),
  EndLocation.Latitude=double(),
  EndLocation.Longitude=double()
)


if(nrow(destinations.df)<1){
  output.df <- cbind(destinations.df,mySegments)
} else {

# Set REST API Request Parameters
start.point <- paste0(start.lon,",",start.lat)
start.name <- "MyCenter"

  
# Determine number of REST API calls needed (max 15 waypoints per call)
max.waypoints <- 15
iterations <- ceiling(nrow(destinations.df)/max.waypoints)

for (iter in 1:iterations){
    
    i.start <- iter*max.waypoints - max.waypoints + 1
    i.end <- iter*max.waypoints
    
    if(nrow(destinations.df)<i.end){
      i.end<-nrow(destinations.df)
    }
    
    waypoint.string <- ""
    for (i in i.start:i.end){
      print(i)
      this.string <- paste0("n:point",i,";ll:",destinations.df$HQ_LONGITUDE[i],",",destinations.df$HQ_LATITUDE[i],"|")
      waypoint.string <- paste0(waypoint.string,this.string)
    }
    waypoint.string <- substr(waypoint.string,1,nchar(waypoint.string)-1) #trim off last character
    
    
    #Construct API Request url for Trade Area
    myURL<-paste0(
      "https://geowebservices.maporama.com/itinerary/distance/onetomany.json", #base url
      "?maporamakey=",api.key, #parameter for API Key
      "&startname=",start.name,
      "&startpoint=",start.point,
      "&travelmode=","vehicle",
      "&unitsystem=","metric",
      "&avoidtollroad=","false",
      "&avoidhighways=","false",
      "&waypoints=",waypoint.string
    )
    
    # Make API Call
    api.result <- fromJSON(txt=myURL,flatten=TRUE)
    
    # Keep segments part of results list
    mySegments <- rbind(mySegments,api.result$Segments)
}

# Bind segments to destinations and output
output.df <- cbind(destinations.df,mySegments)

}