curvature versus slope
  n = 164888 
  X=0, Y = 14.73 +/- 13.32 
  Weighted least-squares fit:  Y = 36.6 + 2.932 X  + -0.03156 X**2 

slope versus dZ, curvature < 5
  n = 34826 
  X=0, Y = 14.06 +/- 6.63 
  Weighted least-squares fit:  Y = 11.9 + 0.139 X  + 0.00231 X**2 
     at X = 100, Y = 48.8 
     effective RMSE xy = 74.4 

slope versus dZ, curvature < 15
  n = 56435 
  X=0, Y = 14.46 +/- 6.31 
  Weighted least-squares fit:  Y = 11.3 + 0.270 X  + 0.00145 X**2 

curvature versus dZ, slope < 10
  n = 37262 
  X=0, Y = 12.86 +/- 5.37 
  Weighted least-squares fit:  Y = 12.5 + 0.508 X  + 0.13225 X**2 


Number of samples 166962
Max dz = 900
Mean dz = 41
RMS dz = 84.2377587546
100cm = 90.039050802 percentile value of dz