curvature versus slope
  n = 581447 
  X=0, Y = 25.90 +/- 16.22 
  Weighted least-squares fit:  Y = 35.9 + 3.047 X  + -0.03477 X**2 

slope versus dZ, curvature < 5
  n = 263816 
  X=0, Y = 8.06 +/- 4.68 
  Weighted least-squares fit:  Y = 7.2 + 1.147 X  + -0.00351 X**2 
     at X = 100, Y = 86.8 
     effective RMSE xy = 135.8 

slope versus dZ, curvature < 15
  n = 386375 
  X=0, Y = 8.44 +/- 4.70 
  Weighted least-squares fit:  Y = 7.6 + 1.133 X  + -0.00353 X**2 

curvature versus dZ, slope < 10
  n = 72552 
  X=0, Y = 13.53 +/- 10.05 
  Weighted least-squares fit:  Y = 12.3 + 2.430 X  + 0.01066 X**2 


Number of samples 589910
Max dz = 900
Mean dz = 42
RMS dz = 63.387695967
100cm = 92.3681578546 percentile value of dz