curvature versus slope
  n = 1380808 
  X=0, Y = 14.89 +/- 12.39 
  Weighted least-squares fit:  Y = 25.5 + 3.977 X  + -0.04450 X**2 

slope versus dZ, curvature < 5
  n = 320395 
  X=0, Y = 6.24 +/- 3.52 
  Weighted least-squares fit:  Y = 75.5 + 0.350 X  + -0.00089 X**2 
     at X = 100, Y = 101.7 
     effective RMSE xy = 106.9 

slope versus dZ, curvature < 15
  n = 622628 
  X=0, Y = 6.24 +/- 3.52 
  Weighted least-squares fit:  Y = 78.2 + 0.166 X  + 0.00103 X**2 

curvature versus dZ, slope < 10
  n = 340084 
  X=0, Y = 77.74 +/- 56.40 
  Weighted least-squares fit:  Y = 82.4 + -0.392 X  + 0.00310 X**2 


Number of samples 1384754
Max dz = 900
Mean dz = 76
RMS dz = 100.876161703
100cm = 61.3999309625 percentile value of dz