curvature versus slope
  n = 388134 
  X=0, Y = 8.14 +/- 5.29 
  Weighted least-squares fit:  Y = 6.5 + 5.124 X  + -0.05700 X**2 

slope versus dZ, curvature < 5
  n = 236134 
  X=0, Y = 16.22 +/- 9.63 
  Weighted least-squares fit:  Y = 12.1 + 0.110 X  + 0.00421 X**2 
     at X = 100, Y = 65.1 
     effective RMSE xy = 100.5 

slope versus dZ, curvature < 15
  n = 352616 
  X=0, Y = 16.49 +/- 10.16 
  Weighted least-squares fit:  Y = 12.1 + 0.189 X  + 0.00341 X**2 

curvature versus dZ, slope < 10
  n = 305954 
  X=0, Y = 12.62 +/- 7.75 
  Weighted least-squares fit:  Y = 12.5 + 0.744 X  + 0.13121 X**2 


Number of samples 389077
Max dz = 800
Mean dz = 13
RMS dz = 21.610182785
100cm = 99.7185647057 percentile value of dz