curvature versus slope
  n = 1422814 
  X=0, Y = 14.74 +/- 12.84 
  Weighted least-squares fit:  Y = 10.3 + 1.559 X  + -0.00907 X**2 

slope versus dZ, curvature < 5
  n = 46282 
  X=0, Y = 3.76 +/- 3.34 
  Weighted least-squares fit:  Y = 2.9 + 0.184 X  + -0.00104 X**2 
     at X = 100, Y = 10.8 
     effective RMSE xy = 16.4 

slope versus dZ, curvature < 15
  n = 192665 
  X=0, Y = 3.25 +/- 2.55 
  Weighted least-squares fit:  Y = 3.4 + 0.108 X  + 0.00086 X**2 

curvature versus dZ, slope < 10
  n = 545781 
  X=0, Y = 3.92 +/- 2.22 
  Weighted least-squares fit:  Y = 3.8 + 0.110 X  + 0.00150 X**2 


Number of samples 1425293
Max dz = 900
Mean dz = 9
RMS dz = 29.9332590942
100cm = 99.8314030869 percentile value of dz
Mean dz (curv<=5) = 3
RMS dz (curv<=5) = 8.42614977318