Currently we are working on an application that needs to show the routes inside malls, airport, inside building. Whether can we able to do the indoor navigation using Google maps sdk for flutter or is there is any other service that will allow us to do indoor navigation.
We have checked google map sdk but we didn't get any ways to implement it.
You cannot use Google maps sdks. Instead you can use Openstreetmaps, Openlayers and GeoJson with Turfjs. This helps you to build your own map on openstreetmaps and integrate GeoJson using openlayers.
for Example reference you can use https://github.com/Masky09/Cendrol-Indoor-map