curvature versus slope
  n = 726320 
  X=0, Y = 6.12 +/- 4.17 
  Weighted least-squares fit:  Y = 7.0 + 4.944 X  + -0.05526 X**2 

slope versus dZ, curvature < 5
  n = 535947 
  X=0, Y = 9.72 +/- 5.80 
  Weighted least-squares fit:  Y = 7.1 + 0.431 X  + 0.00047 X**2 
     at X = 100, Y = 54.9 
     effective RMSE xy = 85.6 

slope versus dZ, curvature < 15
  n = 658579 
  X=0, Y = 9.86 +/- 5.85 
  Weighted least-squares fit:  Y = 7.0 + 0.545 X  + -0.00063 X**2 

curvature versus dZ, slope < 10
  n = 597271 
  X=0, Y = 8.88 +/- 5.16 
  Weighted least-squares fit:  Y = 8.1 + 1.734 X  + -0.01130 X**2 


Number of samples 731874
Max dz = 900
Mean dz = 11
RMS dz = 24.269322199
100cm = 99.1534061874 percentile value of dz