109 lines
2.6 KiB
Go
109 lines
2.6 KiB
Go
|
// Amsterdump is a small program that populates a BigQuery table with
|
||
|
|
// a matrix of origin points scattered around Amsterdam and each
|
||
|
|
// respective points travel time to a given destination.
|
||
|
|
//
|
||
|
|
// The two destinations used here are the Schiphol Airport and
|
||
|
|
// Amsterdam Central station.
|
||
|
|
//
|
||
|
|
// To accomplish this the Google Maps Distance Matrix API [1] is
|
||
|
|
// queried with the points. A visualisation is later done using
|
||
|
|
// BigQuery GeoViz[2].
|
||
|
|
//
|
||
|
|
// [1]: https://developers.google.com/maps/documentation/distance-matrix/start#quotas
|
||
|
|
// [2]: https://bigquerygeoviz.appspot.com/
|
||
|
|
package main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"context"
|
||
|
|
"encoding/json"
|
||
|
|
"fmt"
|
||
|
|
"io/ioutil"
|
||
|
|
"log"
|
||
|
|
"os"
|
||
|
|
|
||
|
|
"googlemaps.github.io/maps"
|
||
|
|
)
|
||
|
|
|
||
|
|
func failOn(err error, msg string) {
|
||
|
|
if err != nil {
|
||
|
|
log.Fatalln(msg, err)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
type LocationResult struct {
|
||
|
|
Address string `json:"address"`
|
||
|
|
URL string `json:"url"`
|
||
|
|
Schiphol *maps.DistanceMatrixElement `json:"schiphol"`
|
||
|
|
Centraal *maps.DistanceMatrixElement `json:"centraal"`
|
||
|
|
}
|
||
|
|
|
||
|
|
type Listing struct {
|
||
|
|
URL string `json:"url"`
|
||
|
|
Address string `json:"address"`
|
||
|
|
}
|
||
|
|
|
||
|
|
func requestMatrix(ctx context.Context, client *maps.Client, listings []Listing) {
|
||
|
|
origins := make([]string, len(listings))
|
||
|
|
for i, l := range listings {
|
||
|
|
origins[i] = l.Address
|
||
|
|
}
|
||
|
|
|
||
|
|
request := &maps.DistanceMatrixRequest{
|
||
|
|
Mode: maps.TravelModeTransit,
|
||
|
|
Units: maps.UnitsMetric,
|
||
|
|
Origins: origins,
|
||
|
|
|
||
|
|
Destinations: []string{
|
||
|
|
"Schiphol Airport",
|
||
|
|
"Amsterdam Centraal",
|
||
|
|
},
|
||
|
|
}
|
||
|
|
|
||
|
|
response, err := client.DistanceMatrix(ctx, request)
|
||
|
|
failOn(err, "could not retrieve distance matrix:")
|
||
|
|
|
||
|
|
for idx, addr := range response.OriginAddresses {
|
||
|
|
result := LocationResult{
|
||
|
|
Address: addr,
|
||
|
|
URL: listings[idx].URL,
|
||
|
|
Schiphol: response.Rows[idx].Elements[0],
|
||
|
|
Centraal: response.Rows[idx].Elements[1],
|
||
|
|
}
|
||
|
|
|
||
|
|
j, _ := json.Marshal(result)
|
||
|
|
fmt.Println(string(j))
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func main() {
|
||
|
|
var listings []Listing
|
||
|
|
input, err := ioutil.ReadFile("fun/amsterdump/input.json")
|
||
|
|
failOn(err, "could not read input file:")
|
||
|
|
|
||
|
|
err = json.Unmarshal(input, &listings)
|
||
|
|
failOn(err, "could not deserialise listings:")
|
||
|
|
|
||
|
|
ctx := context.Background()
|
||
|
|
apiKey := os.Getenv("MAPS_API_KEY")
|
||
|
|
if apiKey == "" {
|
||
|
|
log.Fatalln("API key must be supplied via MAPS_API_KEY")
|
||
|
|
}
|
||
|
|
|
||
|
|
client, err := maps.NewClient(maps.WithAPIKey(apiKey))
|
||
|
|
failOn(err, "could not create Google Maps API client:")
|
||
|
|
|
||
|
|
var chunk []Listing
|
||
|
|
for _, l := range listings {
|
||
|
|
if len(chunk) == 25 {
|
||
|
|
requestMatrix(ctx, client, chunk)
|
||
|
|
chunk = []Listing{}
|
||
|
|
} else {
|
||
|
|
chunk = append(chunk, l)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if len(chunk) > 1 {
|
||
|
|
requestMatrix(ctx, client, chunk)
|
||
|
|
}
|
||
|
|
}
|