curvature versus slope
  n = 512284 
  X=0, Y = 10.66 +/- 8.51 
  Weighted least-squares fit:  Y = 17.8 + 4.266 X  + -0.04800 X**2 

slope versus dZ, curvature < 5
  n = 282505 
  X=0, Y = 5.61 +/- 5.26 
  Weighted least-squares fit:  Y = 5.9 + 0.320 X  + 0.00269 X**2 
     at X = 100, Y = 64.8 
     effective RMSE xy = 101.4 

slope versus dZ, curvature < 15
  n = 381382 
  X=0, Y = 6.09 +/- 5.67 
  Weighted least-squares fit:  Y = 6.1 + 0.407 X  + 0.00187 X**2 

curvature versus dZ, slope < 10
  n = 255691 
  X=0, Y = 7.56 +/- 6.11 
  Weighted least-squares fit:  Y = 7.1 + 1.582 X  + 0.15710 X**2 


Number of samples 519090
Max dz = 900
Mean dz = 22
RMS dz = 60.1082357086
100cm = 95.6279257932 percentile value of dz