curvature versus slope
  n = 366792 
  X=0, Y = 45.75 +/- 24.61 
  Weighted least-squares fit:  Y = 62.0 + 1.620 X  + -0.01729 X**2 

slope versus dZ, curvature < 5
  n = 34076 

  Weighted least-squares fit:  Y = 94.3 + -0.185 X  + 0.00400 X**2 
     at X = 100, Y = 115.9 
     effective RMSE xy = 105.7 

slope versus dZ, curvature < 15
  n = 89952 

  Weighted least-squares fit:  Y = 95.9 + -0.255 X  + 0.00516 X**2 

curvature versus dZ, slope < 10
  n = 2599 
  X=0, Y = 85.57 +/- 29.13 
  Weighted least-squares fit:  Y = 85.2 + 3.282 X  + -0.19334 X**2 


Number of samples 368040
Max dz = 900
Mean dz = 107
RMS dz = 135.628168166
100cm = 51.3283882187 percentile value of dz