目录

Geocoding and Reverse Geocoding

Scenario

Describing a location by latitude and longitude is highly accurate but not intuitive or user-friendly. The system provides the following two conversion capabilities:

A geocode contains multiple attributes that describe location information, such as country, administrative division, street, house number, and address description, making the information easier for users to understand.

Available APIs

The APIs used for conversion between latitude and longitude coordinates and geocodes are described below. For details, see @ohos.geoLocationManager (Geolocation Manager).

API Description
isGeocoderAvailable(): boolean Checks whether the geocoding and reverse geocoding services are available.
getAddressesFromLocation(request: ReverseGeoCodeRequest, callback: AsyncCallback<Array<GeoAddress>>): void Converts coordinates into geographic descriptions through reverse geocoding. This API uses an asynchronous callback to return the result.
getAddressesFromLocationName(request: GeoCodeRequest, callback: AsyncCallback<Array<GeoAddress>>): void Converts geographic descriptions into coordinates through geocoding. This API uses an asynchronous callback to return the result.

How to Develop

The geocoding and reverse geocoding services need to access backend services. Ensure that your device is connected to the network to obtain information.

  1. Import the geoLocationManager module. All functional APIs related to geocoding and reverse geocoding capabilities are provided by this module.

    import { geoLocationManager } from '@kit.LocationKit';

  2. Check whether the geocoding and reverse geocoding services are available.

    • Call isGeocoderAvailable to check whether the geocoding and reverse geocoding services are available. If yes, proceed to step 3. If the services are unavailable, the device does not have the geocoding and reverse geocoding capabilities. Do not use the related APIs.

      import { geoLocationManager } from '@kit.LocationKit';
try {
    let isAvailable = geoLocationManager.isGeocoderAvailable();
} catch (err) {
    console.error("errCode:" + JSON.stringify(err));
}

  3. Obtain the geocoding conversion result.

    • Call getAddressesFromLocation to convert coordinates into geographic descriptions (i.e., location information). Your application can obtain the list of GeoAddress objects that match the coordinates and read the corresponding parameter data based on actual usage requirements.

      let reverseGeocodeRequest:geoLocationManager.ReverseGeoCodeRequest = {"latitude": 31.12, "longitude": 121.11, "maxItems": 1};
try {
    geoLocationManager.getAddressesFromLocation(reverseGeocodeRequest, (err, data) => {
        if (err) {
            console.error('getAddressesFromLocation err: ' + JSON.stringify(err));
        } else {
            console.info('getAddressesFromLocation data: ' + JSON.stringify(data));
        }
    });
} catch (err) {
    console.error("errCode:" + JSON.stringify(err));
}

    • Call getAddressesFromLocationName to convert geographic descriptions (i.e., location information) into coordinates.

      let geocodeRequest:geoLocationManager.GeoCodeRequest = {"description": "No. xx, xx Road, Pudong District, Shanghai", "maxItems": 1};
try {
    geoLocationManager.getAddressesFromLocationName(geocodeRequest, (err, data) => {
        if (err) {
            console.error('getAddressesFromLocationName err: ' + JSON.stringify(err));
        } else {
            console.info('getAddressesFromLocationName data: ' + JSON.stringify(data));
        }
    });
} catch (err) {
    console.error("errCode:" + JSON.stringify(err));
}

      Your application can obtain the list of GeoAddress objects that match the location information, which contains the corresponding coordinate data.

      If the location description to be queried may have duplicate names in multiple places, you can set GeoCodeRequest to specify a longitude and latitude range to efficiently obtain the desired accurate results.