curvature versus slope
  n = 53355 
  X=0, Y = 14.67 +/- 9.68 
  Weighted least-squares fit:  Y = 26.2 + 3.782 X  + -0.04343 X**2 

slope versus dZ, curvature < 5
  n = 19773 
  X=0, Y = 21.86 +/- 8.94 
  Weighted least-squares fit:  Y = 18.3 + -0.173 X  + 0.00317 X**2 
     at X = 100, Y = 32.7 
     effective RMSE xy = 42.5 

slope versus dZ, curvature < 15
  n = 28260 
  X=0, Y = 21.86 +/- 8.94 
  Weighted least-squares fit:  Y = 17.4 + -0.077 X  + 0.00448 X**2 

curvature versus dZ, slope < 10
  n = 12283 
  X=0, Y = 17.29 +/- 4.87 
  Weighted least-squares fit:  Y = 16.8 + 0.963 X  + -0.04096 X**2 


Number of samples 53989
Max dz = 900
Mean dz = 38
RMS dz = 75.0066663704
100cm = 90.6999573987 percentile value of dz