curvature versus slope
  n = 1777435 
  X=0, Y = 12.48 +/- 10.58 
  Weighted least-squares fit:  Y = 23.6 + 4.153 X  + -0.04796 X**2 

slope versus dZ, curvature < 5
  n = 665961 
  X=0, Y = 4.43 +/- 3.20 
  Weighted least-squares fit:  Y = 19.0 + -0.049 X  + 0.00513 X**2 
     at X = 100, Y = 65.4 
     effective RMSE xy = 98.3 

slope versus dZ, curvature < 15
  n = 1209870 
  X=0, Y = 13.37 +/- 11.15 
  Weighted least-squares fit:  Y = 18.7 + 0.033 X  + 0.00443 X**2 

curvature versus dZ, slope < 10
  n = 745569 
  X=0, Y = 19.09 +/- 10.58 
  Weighted least-squares fit:  Y = 19.4 + 0.280 X  + 0.12141 X**2 


Number of samples 1805824
Max dz = 900
Mean dz = 27
RMS dz = 46.7332857822
100cm = 96.1173957152 percentile value of dz