curvature versus slope
  n = 1133839 
  X=0, Y = 10.17 +/- 7.66 
  Weighted least-squares fit:  Y = 9.5 + 4.677 X  + -0.06053 X**2 

slope versus dZ, curvature < 5
  n = 380015 
  X=0, Y = 9.99 +/- 5.50 
  Weighted least-squares fit:  Y = 9.2 + 0.302 X  + 0.00101 X**2 
     at X = 100, Y = 49.5 
     effective RMSE xy = 76.4 

slope versus dZ, curvature < 15
  n = 816938 
  X=0, Y = 10.64 +/- 5.68 
  Weighted least-squares fit:  Y = 9.8 + 0.341 X  + 0.00072 X**2 

curvature versus dZ, slope < 10
  n = 624476 
  X=0, Y = 10.63 +/- 6.21 
  Weighted least-squares fit:  Y = 10.2 + 1.223 X  + 0.04136 X**2 


Number of samples 1152118
Max dz = 500
Mean dz = 16
RMS dz = 28.4077454227
100cm = 98.222491099 percentile value of dz