curvature versus slope
  n = 46432 
  X=0, Y = 52.94 +/- 17.97 
  Weighted least-squares fit:  Y = 59.2 + 2.717 X  + -0.04452 X**2 

slope versus dZ, curvature < 5
  n = 27476 

  Weighted least-squares fit:  Y = -1.0 + 0.718 X  + 0.00081 X**2 
     at X = 100, Y = 78.9 
     effective RMSE xy = 124.0 

slope versus dZ, curvature < 15
  n = 40579 

  Weighted least-squares fit:  Y = -2.3 + 0.774 X  + 0.00038 X**2 

curvature versus dZ, slope < 10
  n = 30 
  X=0, Y = 7.27 +/- 6.13 
  Weighted least-squares fit:  Y = 7.3 + 4.614 X  + -1.45650 X**2 


Number of samples 46696
Max dz = 900
Mean dz = 42
RMS dz = 57.6801525657
100cm = 96.1260065102 percentile value of dz