curvature versus slope
  n = 520279 
  X=0, Y = 13.15 +/- 7.72 
  Weighted least-squares fit:  Y = 15.8 + 4.210 X  + -0.04636 X**2 

slope versus dZ, curvature < 5
  n = 274901 
  X=0, Y = 9.58 +/- 4.76 
  Weighted least-squares fit:  Y = 10.0 + 0.355 X  + 0.00050 X**2 
     at X = 100, Y = 50.6 
     effective RMSE xy = 77.9 

slope versus dZ, curvature < 15
  n = 400173 
  X=0, Y = 9.22 +/- 4.95 
  Weighted least-squares fit:  Y = 9.9 + 0.410 X  + 0.00045 X**2 

curvature versus dZ, slope < 10
  n = 179216 
  X=0, Y = 12.90 +/- 6.82 
  Weighted least-squares fit:  Y = 11.5 + 1.477 X  + 0.11596 X**2 


Number of samples 526883
Max dz = 900
Mean dz = 20
RMS dz = 45.9020696701
100cm = 97.7245422608 percentile value of dz