If you click the mouse, you will open this help file. If you like, you can set any values for the width and height of the applet. TrackingTime is to set the tracking time interval in millisecond. If you don't set the value, the default value 1000 ms will be used. This API is for tracking a moving object and displaying it on the map.
Parameter symbol is the filename of the symbol.
Parameter refresh is to decide whether the screen should be repainted or not before the symbol is drawn. This API is to draw a symbol with NAC on the map. If you know the NAC of a house for example, you can simply use the NAC as the coordinates to draw a symbol on the map. Since the function draws a symbol at a time, it can be used to draw as many traces as you want by calling the API multiple times for each time step with appropriate control of repaint of the map. For example, you can draw the locations of two vehicles that the first call of the API repaints the map and the second call does not repaint.