plotting a Latitude-Longitude path by qwt on a map

Hi,
I need first to import a map on the background of my QwtPlot. Then I need to plot a path (vertical axe is Latitude and horizontal one is Longitude) on this map that Lat and Lon be displayed correctly on the map. Please help me to do:

1- How importing an offline map (like google map) on the background that each point of this map (I mean each [lat, lon] on this map) be related to the vertical axe (display Lat of the map) and horizontal axe (display Lon of the map)?
2- And then after plotting the path (based on lat-lon), this path be displayed on the map?

thanks