curvature versus slope
  n = 113540 
  X=0, Y = 62.96 +/- 22.83 
  Weighted least-squares fit:  Y = 71.0 + 1.340 X  + -0.01472 X**2 

slope versus dZ, curvature < 5
  n = 37927 

  Weighted least-squares fit:  Y = 15.3 + 0.295 X  + 0.00269 X**2 
     at X = 100, Y = 71.7 
     effective RMSE xy = 110.1 

slope versus dZ, curvature < 15
  n = 74040 

  Weighted least-squares fit:  Y = 15.2 + 0.355 X  + 0.00225 X**2 

curvature versus dZ, slope < 10
  n = 732 
  X=0, Y = 16.45 +/- 7.74 
  Weighted least-squares fit:  Y = 16.0 + 4.055 X  + -0.50620 X**2 


Number of samples 114468
Max dz = 900
Mean dz = 51
RMS dz = 125.215813698
100cm = 87.9057902645 percentile value of dz