curvature versus slope
  n = 1188893 
  X=0, Y = 46.35 +/- 22.13 
  Weighted least-squares fit:  Y = 54.0 + 2.121 X  + -0.02308 X**2 

slope versus dZ, curvature < 5
  n = 319138 
  X=0, Y = 2.24 +/- 1.45 
  Weighted least-squares fit:  Y = 2.6 + 0.431 X  + -0.00155 X**2 
     at X = 100, Y = 30.2 
     effective RMSE xy = 47.2 

slope versus dZ, curvature < 15
  n = 600971 
  X=0, Y = 2.24 +/- 1.45 
  Weighted least-squares fit:  Y = 4.3 + 0.295 X  + 0.00066 X**2 

curvature versus dZ, slope < 10
  n = 12463 
  X=0, Y = 6.26 +/- 4.26 
  Weighted least-squares fit:  Y = 5.3 + 1.773 X  + -0.03092 X**2 


Number of samples 1220715
Max dz = 900
Mean dz = 34
RMS dz = 56.4358042381
100cm = 91.9487349627 percentile value of dz