Rescue PC

Add google map link to iPhone Contacts

Format of the field
comgooglemaps://?daddr=Latitude,Longitude&directionsmode=driving
e.g.
comgooglemaps://?daddr=52.??????,-1.??????&directionsmode=driving (where ??? are numbers)

Get the Long Lat from Google Maps
https://maps.google.com/
find address, then right click on map and select "whats here" in search bar Latitude and Longitude will appear

Edit your iPhone contact
Create a new "URL" type field that you may call "GPS" or any name.
Fill this field with the format above with your GPS coordinates:

Cheers
Rescue PC