curvature versus slope
  n = 421164 
  X=0, Y = 14.20 +/- 13.20 
  Weighted least-squares fit:  Y = 35.2 + 3.098 X  + -0.03543 X**2 

slope versus dZ, curvature < 5
  n = 95809 
  X=0, Y = 18.09 +/- 7.69 
  Weighted least-squares fit:  Y = 14.2 + 0.273 X  + 0.00135 X**2 
     at X = 100, Y = 55.0 
     effective RMSE xy = 83.4 

slope versus dZ, curvature < 15
  n = 157141 
  X=0, Y = 17.69 +/- 7.21 
  Weighted least-squares fit:  Y = 14.8 + 0.297 X  + 0.00107 X**2 

curvature versus dZ, slope < 10
  n = 104967 
  X=0, Y = 14.81 +/- 8.60 
  Weighted least-squares fit:  Y = 14.6 + 1.758 X  + 0.03063 X**2 


Number of samples 428094
Max dz = 900
Mean dz = 40
RMS dz = 64.5368112011
100cm = 90.4051446645 percentile value of dz