Trying to build a Campus Map – April 26, 2023 at 06:44AM

I am trying to build a navigation solution for my college campus which will work on Android devices. I used polylines on Google Maps to create buildings, but I cannot create additional walking paths that are not visible on google maps. I tried using KML files using google earth but still faced the same issue. Is there any way I can add additional routes only for my project or any software with which I can make a whole new map and use it in Android apps?