curvature versus slope
  n = 1220602 
  X=0, Y = 6.18 +/- 4.35 
  Weighted least-squares fit:  Y = 8.3 + 5.278 X  + -0.05901 X**2 

slope versus dZ, curvature < 5
  n = 1038878 
  X=0, Y = 12.85 +/- 7.07 
  Weighted least-squares fit:  Y = 12.9 + 0.335 X  + 0.00091 X**2 
     at X = 100, Y = 55.5 
     effective RMSE xy = 84.8 

slope versus dZ, curvature < 15
  n = 1135352 
  X=0, Y = 12.88 +/- 7.08 
  Weighted least-squares fit:  Y = 12.6 + 0.462 X  + -0.00031 X**2 

curvature versus dZ, slope < 10
  n = 1015492 
  X=0, Y = 13.75 +/- 8.03 
  Weighted least-squares fit:  Y = 13.5 + 3.231 X  + -0.08713 X**2 


Number of samples 1232844
Max dz = 900
Mean dz = 16
RMS dz = 25.903667694
100cm = 98.8938584282 percentile value of dz