relation between autoscrollposition and x,y

The relationship between the two is that the AutoScrollPosition is offsetting the PictureBox.Location relative to the Panel.Location, and the point in the PictureBox is an offset from the PistureBox.Location.

[Edit]
To change the AutoScrollPosition, you need to assign it a Point object that represents the offset that you want it to move to. In other words:

panel1.AutoScrollPosition = new Point(50,100);

would cause the horizontal scrollbar to move 50 points to the right and the vertical scrollbar would move down 100 points. It sounds like you are trying to display a map and have it automatically center when the user clicks on it, is that right? If so, your Mouseclick event would do something like this:

private void pictureBox1_MouseClick ( object sender, MouseEventArgs e )
{
	Point panelcenter = new Point ( ( this.panel1.Width / 2 ), ( this.panel1.Height / 2 ) ); // find the centerpoint of the panel
	Point offsetinpicturebox = new Point ( ( this.pictureBox1.Location.X + e.Location.X ), ( this.pictureBox1.Location.Y + e.Location.Y ) ); // find the offset of the mouse click
	Point offsetfromcenter = new Point ( ( panelcenter.X - offsetinpicturebox.X ), ( panelcenter.Y - offsetinpicturebox.Y ) ); // find the difference between the mouse click and the center

	this.panel1.AutoScrollPosition = new Point ( 
		( Math.Abs ( this.panel1.AutoScrollPosition.X ) + ( -1 * offsetfromcenter.X ) ), 
		( Math.Abs ( this.panel1.AutoScrollPosition.Y ) + ( -1 * offsetfromcenter.Y ) ) 
	);
}

Note: It is important to realize that when you retrieve the AutoScrollPosition, it will return with negative values. However, when you assign it, you need to assign positive values.