curvature versus slope
  n = 89689 
  X=0, Y = 16.03 +/- 13.46 
  Weighted least-squares fit:  Y = 32.4 + 3.212 X  + -0.03548 X**2 

slope versus dZ, curvature < 5
  n = 18610 
  X=0, Y = 9.77 +/- 2.66 
  Weighted least-squares fit:  Y = 12.4 + 0.100 X  + 0.00122 X**2 
     at X = 100, Y = 34.6 
     effective RMSE xy = 50.8 

slope versus dZ, curvature < 15
  n = 34495 
  X=0, Y = 12.64 +/- 8.06 
  Weighted least-squares fit:  Y = 12.8 + 0.149 X  + 0.00130 X**2 

curvature versus dZ, slope < 10
  n = 19798 
  X=0, Y = 12.42 +/- 6.67 
  Weighted least-squares fit:  Y = 12.0 + 1.555 X  + -0.01660 X**2 


Number of samples 90581
Max dz = 900
Mean dz = 37
RMS dz = 88.3855191759
100cm = 91.9861781168 percentile value of dz