curvature versus slope
  n = 788437 
  X=0, Y = 47.23 +/- 26.11 
  Weighted least-squares fit:  Y = 70.8 + 1.384 X  + -0.01367 X**2 

slope versus dZ, curvature < 5
  n = 7423 

  Weighted least-squares fit:  Y = 52.6 + 0.253 X  + -0.00069 X**2 
     at X = 100, Y = 71.1 
     effective RMSE xy = 75.1 

slope versus dZ, curvature < 15
  n = 45567 

  Weighted least-squares fit:  Y = 56.4 + 0.269 X  + 0.00026 X**2 

curvature versus dZ, slope < 10
  n = 508 

  Weighted least-squares fit:  Y = 48.3 + 5.315 X  + -0.48109 X**2 


Number of samples 799246
Max dz = 900
Mean dz = 99
RMS dz = 131.316411769
100cm = 59.8114973362 percentile value of dz