curvature versus slope
  n = 71171 
  X=0, Y = 35.21 +/- 29.61 
  Weighted least-squares fit:  Y = 74.7 + 1.054 X  + -0.01030 X**2 

slope versus dZ, curvature < 5
  n = 1930 

  Weighted least-squares fit:  Y = 99.4 + 0.918 X  + -0.00415 X**2 
     at X = 100, Y = 149.7 
     effective RMSE xy = 175.9 

slope versus dZ, curvature < 15
  n = 5230 

  Weighted least-squares fit:  Y = 98.7 + 1.192 X  + -0.00568 X**2 

curvature versus dZ, slope < 10
  n = 913 
  X=0, Y = 105.67 +/- 8.86 
  Weighted least-squares fit:  Y = 105.2 + 0.119 X  + 0.65052 X**2 


Number of samples 71532
Max dz = 900
Mean dz = 144
RMS dz = 195.05127531
100cm = 38.3115249119 percentile value of dz