curvature versus slope
  n = 1085743 
  X=0, Y = 22.10 +/- 15.84 
  Weighted least-squares fit:  Y = 41.4 + 2.748 X  + -0.02870 X**2 

slope versus dZ, curvature < 5
  n = 86553 
  X=0, Y = 7.33 +/- 2.68 
  Weighted least-squares fit:  Y = 6.7 + 0.158 X  + 0.00068 X**2 
     at X = 100, Y = 29.3 
     effective RMSE xy = 44.7 

slope versus dZ, curvature < 15
  n = 214815 
  X=0, Y = 7.33 +/- 2.68 
  Weighted least-squares fit:  Y = 6.6 + 0.223 X  + 0.00068 X**2 

curvature versus dZ, slope < 10
  n = 37008 
  X=0, Y = 6.94 +/- 4.38 
  Weighted least-squares fit:  Y = 6.9 + 0.960 X  + 0.06889 X**2 


Number of samples 1098079
Max dz = 900
Mean dz = 42
RMS dz = 69.0144912319
100cm = 87.755252582 percentile value of dz