locating coordinates in Qt qml offline map

  • Hi! i am trying to use offline map for my application written in C++ using QT. i have downloaded tiles for a small area and now i want the marker should point to a particular coordinate and this coordinate when altered by user should be reflected on offline MAP. i have downloaded tiles using maperitive software, i am wondering since these tiles are in png format how to calibrate these images according to their actual coordinate, has anybody did the similar task please guide me if anybody has any knowledge.