How to Convert Latitude and Longitude to Address with Google Map API in Flutter

In this example, we are going to show you how to convert location coordinates: latitude and longitude to place address using Google Map's geocoding API in Flutter App. We will use Google Map's rest API to fetch addresses. See the example, below:

Before Stating, go to your google console and activate "Geocoding API" on the Google Map platform > API:

And also get the API Key from the "credentials" tab.

The API key is necessary to authenticate on REST API.

Add geocoding Flutter packages to your project by adding the following lines in pubspec.yaml file:

dependencies:
  flutter:
    sdk: flutter
  geocoding: ^2.0.1

Now get the information about places by longitude and latitude using the code below:

List<Placemark> placemarks = await placemarkFromCoordinates(latitude, longitude);
String palcename = placemarks.first.administrativeArea.toString() + ", " +  placemarks.first.street.toString();

How to Fetch Address of Latitude and Longitude from Google Map API?

In this example, we are going to use the REST API of the Google Map platform to convert the latitude and longitude. You can look at official documentation of Reverse geocoding request and response:

To get Address from Coordinates, you have to request to the following URL format:

https://maps.googleapis.com/maps/api/geocode/json?latlng=27.6669987,85.3071003&key=API_KEY

Replate, the latitude, longitude, and API_KEY with your values. The response from the URL will be JSON data, and it will look like below:

{
   "plus_code" : {
      "compound_code" : "M884+QRX Lalitpur, Nepal",
      "global_code" : "7MV7M884+QRX"
   },
   "results" : [
      {
         "address_components" : [
            {
               "long_name" : "M884+PQQ",
               "short_name" : "M884+PQQ",
               "types" : [ "plus_code" ]
            },
            {
               "long_name" : "Ekantakuna",
               "short_name" : "Ekantakuna",
               "types" : [ "political", "sublocality", "sublocality_level_1" ]
            },
            {
               "long_name" : "Lalitpur",
               "short_name" : "Lalitpur",
               "types" : [ "locality", "political" ]
            },
            {
               "long_name" : "Bagmati",
               "short_name" : "Bagmati",
               "types" : [ "administrative_area_level_2", "political" ]
            },
            {
               "long_name" : "Bagmati Province",
               "short_name" : "Bagmati Province",
               "types" : [ "administrative_area_level_1", "political" ]
            },
            {
               "long_name" : "Nepal",
               "short_name" : "NP",
               "types" : [ "country", "political" ]
            },
            {
               "long_name" : "44600",
               "short_name" : "44600",
               "types" : [ "postal_code" ]
            }
         ],
         "formatted_address" : "M884+PQQ, Lalitpur 44600, Nepal",
         "geometry" : {
            "bounds" : {
               "northeast" : {
                  "lat" : 27.6669181,
                  "lng" : 85.307013
               },
               "southwest" : {
                  "lat" : 27.666812,
                  "lng" : 85.30690349999999
               }
            },
            "location" : {
               "lat" : 27.6668718,
               "lng" : 85.3069672
            },
            "location_type" : "ROOFTOP",
            "viewport" : {
               "northeast" : {
                  "lat" : 27.66821403029151,
                  "lng" : 85.30830723029149
               },
               "southwest" : {
                  "lat" : 27.6655160697085,
                  "lng" : 85.30560926970848
               }
            }
         },
         "place_id" : "ChIJeQua9S4Y6zkR8qYX17Ia99A",
         "types" : [ "premise" ]
      },

<More Addresses>

Now, we will use this REST API to convert Location latitude and longitude to address. See the example below for the references:

Before going to the Flutter App example code, first, add dio package in your project by adding the following lines in pubspec.yaml file:

dependencies:
  flutter:
    sdk: flutter
  dio: ^4.0.4

Dio package will be used for HTTP requests.

import 'package:dio/dio.dart';
import 'package:flutter/material.dart';

void main(){
  runApp(MyApp());
}

class MyApp extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Home(),
    );
  }
}

class Home extends StatefulWidget{
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {

  String googleApikey = "API_KEY";
  double latitude = 27.666994; //latitude
  double longitude = 85.309289; //longitude

  String address = "";

  @override
  void initState() {
    convertToAddress(latitude, longitude, googleApikey); //call convert to address 
    super.initState();
  }

  convertToAddress(double lat, double long, String apikey) async {
      Dio dio = Dio();  //initilize dio package
      String apiurl = "https://maps.googleapis.com/maps/api/geocode/json?latlng=$lat,$long&key=$apikey";
    
      Response response = await dio.get(apiurl); //send get request to API URL

      if(response.statusCode == 200){ //if connection is successful
          Map data = response.data; //get response data
          if(data["status"] == "OK"){ //if status is "OK" returned from REST API
              if(data["results"].length > 0){ //if there is atleast one address
                 Map firstresult = data["results"][0]; //select the first address

                 address = firstresult["formatted_address"]; //get the address

                 //you can use the JSON data to get address in your own format
                 
                 setState(() {
                    //refresh UI
                 });
              }
          }else{
             print(data["error_message"]);
          }
      }else{
         print("error while fetching geoconding data");
      }  
  }

  @override
  Widget build(BuildContext context) {
    return  Scaffold(
          appBar: AppBar( 
             title: Text("Get Address from Google Map API"),
             backgroundColor: Colors.redAccent,
          ),
          body: Container(
             padding: EdgeInsets.all(30),
             child: Column(
               children: [
                    Text("Latitude: $latitude", style: TextStyle(fontSize: 25),),
                    Text("Longitude: $longitude", style: TextStyle(fontSize: 25)),
                    Text("Formatted Address: $address", 
                                  style: TextStyle(fontSize: 20), 
                                  textAlign: TextAlign.center,),
               ],
             ),
          )
       );
  }
}

You can use this code according to your requirement on your project. The output of this example will look like below:

In this way, you can convert location coordinates: latitude and longitude to Place addresses using Google Map Platform REST API in Flutter App.

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