curvature versus slope
  n = 105063 
  X=0, Y = 57.12 +/- 24.39 
  Weighted least-squares fit:  Y = 59.9 + 1.953 X  + -0.02081 X**2 

slope versus dZ, curvature < 5
  n = 18399 

  Weighted least-squares fit:  Y = 14.6 + 0.798 X  + -0.00317 X**2 
     at X = 100, Y = 62.8 
     effective RMSE xy = 95.9 

slope versus dZ, curvature < 15
  n = 38380 

  Weighted least-squares fit:  Y = 21.8 + 0.402 X  + 0.00134 X**2 

curvature versus dZ, slope < 10
  n = 816 
  X=0, Y = 23.59 +/- 16.24 
  Weighted least-squares fit:  Y = 23.9 + 2.843 X  + -0.56697 X**2 


Number of samples 106455
Max dz = 900
Mean dz = 66
RMS dz = 108.443533694
100cm = 82.4827391856 percentile value of dz