@eva thank you
i wanted one more help from you.i was not able to place the markers exactly on the road.like i have to detect the road and place the markers on the road.but i am not able to set like that.markers are getting placed according to the lattitude of my mobiles position.
Did you try to modify the altitude when you define a GeoLocation?
Yes this is possible. Please refer to our documentation section here 'Limiting Visible POIs'.