How to Use Maps Contacts on Your iPhone
Your iPhone's Maps feature has a trick called, Maps Contacts. In a nutshell, this puts the friends and family in your Contacts list on a map. To use the Contacts feature in Maps, tap the bookmarks icon in any search field, and then tap the Contacts button at the bottom of the screen. To see a map of a contact’s location, tap the contact’s name in the list.
To limit the Contacts list to specific groups (assuming that you have some groups in your Contacts list), tap the Groups button in the top-left corner of the screen and then tap the name of the group. Now only contacts in this group are displayed in the list.
When you’re finished using the Contacts list, tap the Done button in the top-right corner of the screen to return to the map.