curvature versus slope
  n = 521117 
  X=0, Y = 20.88 +/- 17.36 
  Weighted least-squares fit:  Y = 50.4 + 2.438 X  + -0.02694 X**2 

slope versus dZ, curvature < 5
  n = 60603 
  X=0, Y = 12.12 +/- 4.08 
  Weighted least-squares fit:  Y = 9.8 + 0.294 X  + 0.00180 X**2 
     at X = 100, Y = 57.1 
     effective RMSE xy = 88.4 

slope versus dZ, curvature < 15
  n = 130512 
  X=0, Y = 12.12 +/- 4.08 
  Weighted least-squares fit:  Y = 9.8 + 0.430 X  + 0.00082 X**2 

curvature versus dZ, slope < 10
  n = 44355 
  X=0, Y = 10.34 +/- 7.27 
  Weighted least-squares fit:  Y = 10.7 + 1.674 X  + 0.04490 X**2 


Number of samples 528136
Max dz = 900
Mean dz = 50
RMS dz = 81.7312669668
100cm = 85.6677068028 percentile value of dz