curvature versus slope
  n = 2814534 
  X=0, Y = 4.16 +/- 1.96 
  Weighted least-squares fit:  Y = 1.8 + 5.301 X  + -0.09961 X**2 

slope versus dZ, curvature < 5
  n = 2306459 
  X=0, Y = 5.20 +/- 3.30 
  Weighted least-squares fit:  Y = 5.7 + 0.630 X  + -0.00386 X**2 
     at X = 100, Y = 30.2 
     effective RMSE xy = 46.6 

slope versus dZ, curvature < 15
  n = 2754916 
  X=0, Y = 5.61 +/- 3.64 
  Weighted least-squares fit:  Y = 5.8 + 0.691 X  + -0.00356 X**2 

curvature versus dZ, slope < 10
  n = 2687351 
  X=0, Y = 7.46 +/- 4.76 
  Weighted least-squares fit:  Y = 7.4 + 1.044 X  + 0.10731 X**2 


Number of samples 2816196
Max dz = 300
Mean dz = 7
RMS dz = 10.7238052948
100cm = 99.9294438313 percentile value of dz