Geocoding and Reverse Geocoding Capabilities

When to Use

Describing a location using coordinates is accurate, but neither intuitive nor user-friendly.

With the geocoding and reverse geocoding capabilities, you will be able to convert geographic description into specific coordinates and vice versa. The geocoding information describes a location using several attributes, including the country, administrative region, street, house number, and address, etc.

Available APIs

The following table describes APIs available for mutual conversion between coordinates and location information.

Table1 APIs for geocoding and reverse geocoding

API	Description
isGeoServiceAvailable(callback: AsyncCallback<boolean>) : void	Checks whether the (reverse) geocoding service is available. This function uses an asynchronous callback to return the result.
isGeoServiceAvailable() : Promise<boolean>	Checks whether the (reverse) geocoding service is available. This function uses a promise to return the result.
getAddressesFromLocation(request: ReverseGeoCodeRequest, callback: AsyncCallback<Array<GeoAddress>>) : void	Converts coordinates into geographic description through reverse geocoding. This function uses an asynchronous callback to return the result.
getAddressesFromLocation(request: ReverseGeoCodeRequest) : Promise<Array<GeoAddress>>;	Converts coordinates into geographic description through reverse geocoding. This function uses a promise to return the result.
getAddressesFromLocationName(request: GeoCodeRequest, callback: AsyncCallback<Array<GeoAddress>>) : void	Converts geographic description into coordinates through geocoding. This function uses an asynchronous callback to return the result.
getAddressesFromLocationName(request: GeoCodeRequest) : Promise<Array<GeoAddress>>	Converts geographic description into coordinates through geocoding. This function uses a promise to return the result.

How to Develop

Note： The GeoConvert instance needs to access backend services to obtain information. Therefore, before performing the following steps, ensure that your device is connected to the network.

Import the geolocation module by which you can implement all APIs related to the geocoding and reverse geocoding conversion capabilities.
```
import geolocation from '@ohos.geolocation';
```
Obtain the conversion result.
- Call getAddressesFromLocation to convert coordinates into geographical location information.
```
var reverseGeocodeRequest = {"latitude": 31.12, "longitude": 121.11, "maxItems": 1};
geolocation.getAddressesFromLocation(reverseGeocodeRequest, (data) => {
    console.log('getAddressesFromLocation: ' + JSON.stringify(data));
});
```
  Your application can obtain the GeoAddress list that matches the specified coordinates and then read location information from it. For details, see the API Reference.
- Call getAddressesFromLocationName to convert geographic description into coordinates.
```
var geocodeRequest = {"description": "No. xx, xx Road, Pudong District, Shanghai", "maxItems": 1};
geolocation.getAddressesFromLocationName(geocodeRequest, (data) => {
    console.log('getAddressesFromLocationName: ' + JSON.stringify(data));
});
```
  Your application can obtain the GeoAddress list that matches the specified location information and read coordinates from it. For details, see the API Reference.
  
  To improve the accuracy of location results, you can set the longitude and latitude ranges in GeoCodeRequest.