curvature versus slope
  n = 1731329 
  X=0, Y = 11.07 +/- 8.95 
  Weighted least-squares fit:  Y = 12.9 + 4.473 X  + -0.04915 X**2 

slope versus dZ, curvature < 5
  n = 645003 
  X=0, Y = 9.24 +/- 7.89 
  Weighted least-squares fit:  Y = 12.0 + 0.441 X  + -0.00083 X**2 
     at X = 100, Y = 47.8 
     effective RMSE xy = 72.7 

slope versus dZ, curvature < 15
  n = 1212385 
  X=0, Y = 9.62 +/- 8.02 
  Weighted least-squares fit:  Y = 13.3 + 0.446 X  + -0.00077 X**2 

curvature versus dZ, slope < 10
  n = 737937 
  X=0, Y = 12.85 +/- 9.22 
  Weighted least-squares fit:  Y = 12.4 + 3.170 X  + -0.07150 X**2 


Number of samples 1761737
Max dz = 900
Mean dz = 21
RMS dz = 34.4383507154
100cm = 98.1029518027 percentile value of dz