If you are using a desktop / laptop machine, it is using your IP to geolocate you so it could be far away from your actual position. If you are using a VPN, you might even end up in another country!
If you are using a tablet, Maps Pro will grab the location from the internal GPS chip. If you are using an external GPS, please check this documentation:
How can I use my USB / Bluetooth GPS receiver?
Maps Pro allows you to change that geolocation, just click on the map > My position > Set as my default location