curvature versus slope
  n = 2304632 
  X=0, Y = 10.40 +/- 7.47 
  Weighted least-squares fit:  Y = 12.9 + 4.939 X  + -0.05837 X**2 

slope versus dZ, curvature < 5
  n = 1084724 
  X=0, Y = 7.17 +/- 5.11 
  Weighted least-squares fit:  Y = 10.8 + 0.405 X  + -0.00062 X**2 
     at X = 100, Y = 45.1 
     effective RMSE xy = 68.7 

slope versus dZ, curvature < 15
  n = 1791799 
  X=0, Y = 7.36 +/- 5.17 
  Weighted least-squares fit:  Y = 12.1 + 0.427 X  + -0.00066 X**2 

curvature versus dZ, slope < 10
  n = 1190271 
  X=0, Y = 10.56 +/- 7.32 
  Weighted least-squares fit:  Y = 11.9 + 3.029 X  + -0.09820 X**2 


Number of samples 2352412
Max dz = 900
Mean dz = 20
RMS dz = 34.6554469023
100cm = 97.7237405693 percentile value of dz