Does anyone know why if you have track over ground that is at 0 for height and you then use the smooth spline tool it lowers the groung to -0.19 or -0.2? I had it do this while I was checking track going through mountains where my track height is 0. Sometimes when I use smooth spline instead of it taken the ground up or down to meet the track it just moves the track and the ground down into a hole. Is there a right or wrong way to use this tool?Also I noticed that some of the track spline points in surveyor show up yellow and others are white. Is there a reason for this?