How to get accurate Map for Waypoints setting

[AAC]

I set waypoints on the phone map in a farm I found the enlarged homepoint image (two bran houses) were blurry. Even I set the waypoint line to force flying between two bran houses which is 50 feet in distance, I found the real flying route was not accurate. Just wondering if there is more accurate measurement option to set the waypoints flying route or this is normal, I have to accept it ?