How to use MapTrackView ?

Thank you for your answer.

Ok, i'll try to be clearer, (sry for my english)

I would like to use mapview as datafield in order to display map with marker during activity.

To do that, I extend WatchUi.MapTrackView.

class iqmapView extends WatchUi.MapTrackView {

initialize() running without error :

function initialize() {
        MapTrackView.initialize();
        setMapMode(WatchUi.MAP_MODE_PREVIEW);
        
        var top_left = new Position.Location({:latitude => 38.85695, :longitude =>-94.80051, :format => :degrees});
        var bottom_right = new Position.Location({:latitude => 38.85391, :longitude =>-94.7963, :format => :degrees});
        MapTrackView.setMapVisibleArea(top_left, bottom_right);
		 
        
        MapTrackView.setScreenVisibleArea(0, System.getDeviceSettings().screenHeight / 2, System.getDeviceSettings().screenWidth, System.getDeviceSettings().screenHeight);
    	System.print("inited");
    }

but, after last 'print', nothing and faild message "Failed to start CIQ Application" appears in console