Google Map Issue - Ionic 2 - google-maps

Question

Google map shows in the browser but when I run command
ionic run android
it build successfully and launch the app but everything works fine except Google map there are no errors in chrome://inspect it just says DEVICE READY FIRED AFTER 630 ms but no error for google map. I did register app on console.developers.google.com got the key and using it in www/index.html in the head but still no changes. Please help thank you.
home.ts (Map function is inside of this file)
// Get the current location
Geolocation.getCurrentPosition().then((position) => {
// Set latitude and longtitude variable
this.lat = position.coords.latitude;
this.long = position.coords.longitude;
// This function will get the name of the city where user is located
this.getCityName(this.lat, this.long);
// this function sets up the google map
let latLng = new google.maps.LatLng(position.coords.latitude, position.coords.longitude);
let mapOptions = {
center: latLng,
zoom: 11,
mapTypeId: google.maps.MapTypeId.ROADMAP
}
var mapi = new google.maps.Map(this.mapDiv.nativeElement, mapOptions);
// Below code is provided by a ai pollution control website (http://aqicn.org/faq/2015-09-18/map-web-service-real-time-air-quality-tile-api/)
// haven't changed anything in below code copied as it is from web
var waqiMapOverlay = new google.maps.ImageMapType({
getTileUrl: function(coord, zoom) {
return 'http://tiles.aqicn.org/tiles/usepa-aqi/' + zoom + "/" + coord.x + "/" + coord.y + ".png?token=_TOKEN_ID_";
},
name: "Air Quality",
});
// Insert above received data into map
mapi.overlayMapTypes.insertAt(0,waqiMapOverlay);
`

Answer 1

Probably your map is not getting coordinates(position.coords.latitude, position.coords.longitude) , that's why your map is not rendering. try with navigator.Geoloaction.getCurrentPosition... or check if any plugin is required to get user geolocation. & prefer to give some fallback coordinates.
this.lat = position.coords.latitude || "21.1610858";
this.long = position.coords.longitude || "79.0725101";