Simple Street Map Mobile App

In my country, many people don't know their street address. It is a bit complicated to give directions to some places. I am trying to build a mobile server-client app for getting directions. In this app, every owner of a mobile phone can acquire its current GPS position and associate it with an email account. Once the association between the email address and the GPS position is done, it is recorded in a database. To give its direction, the mobile user will just give its email address to the user that want to go there. So when someone wants to go to the place of a registered user, he enters the email account of the registered user and get the GPS position + direction to that registered user. The directions can be from the current acquired position on the phone or from another registred user. The user can change its main position any time, but there should be records of all changes in GPS position with the date of change. The mobile app user can have a list of favorites email addresses (GPS position). There will be editor of the web platform that can enter GPS position for famous/strategic landmarks/other users positions. The landmarks can be email address as well of just regular label. The editors can edit landmarks any time. These landmarks can appear on top of the map as a landmarks layer. There will be an administrator that can manage the editors of the system and oversees all transactions on the system. Each request for directions will be logged in the system. The app should run on both Android, Iphone, web, and the administration interface accessible from the web. This app can be done using Google Maps or Openstreet Maps