public void Init(Map2d g)
{
galaxy = g;
xlines = GridId.XLines(galaxy.TopRight.X);
xlines[0] = galaxy.TopLeft.X;
zlines = GridId.ZLines(galaxy.TopLeft.Y); // in numeric incr order
zlines[0] = galaxy.BottomLeft.Y;
ClickToZoom = false;
includedgridid = new List <int>();
}