curvature versus slope
  n = 374332 
  X=0, Y = 10.32 +/- 7.18 
  Weighted least-squares fit:  Y = 12.8 + 4.486 X  + -0.05070 X**2 

slope versus dZ, curvature < 5
  n = 213032 
  X=0, Y = 9.47 +/- 5.85 
  Weighted least-squares fit:  Y = 8.3 + 0.261 X  + 0.00020 X**2 
     at X = 100, Y = 36.4 
     effective RMSE xy = 55.7 

slope versus dZ, curvature < 15
  n = 297108 
  X=0, Y = 9.60 +/- 6.02 
  Weighted least-squares fit:  Y = 8.4 + 0.250 X  + 0.00105 X**2 

curvature versus dZ, slope < 10
  n = 223411 
  X=0, Y = 10.29 +/- 6.21 
  Weighted least-squares fit:  Y = 9.5 + 0.578 X  + 0.04957 X**2 


Number of samples 382179
Max dz = 900
Mean dz = 17
RMS dz = 39.3192065027
100cm = 97.3096376305 percentile value of dz