curvature versus slope
  n = 206421 
  X=0, Y = 7.62 +/- 5.57 
  Weighted least-squares fit:  Y = 9.7 + 4.700 X  + -0.05346 X**2 

slope versus dZ, curvature < 5
  n = 136740 
  X=0, Y = 9.46 +/- 5.55 
  Weighted least-squares fit:  Y = 7.7 + 0.297 X  + 0.00010 X**2 
     at X = 100, Y = 38.4 
     effective RMSE xy = 59.1 

slope versus dZ, curvature < 15
  n = 173294 
  X=0, Y = 9.45 +/- 5.43 
  Weighted least-squares fit:  Y = 7.6 + 0.363 X  + 0.00034 X**2 

curvature versus dZ, slope < 10
  n = 150373 
  X=0, Y = 9.13 +/- 5.47 
  Weighted least-squares fit:  Y = 8.5 + 1.025 X  + 0.09076 X**2 


Number of samples 209826
Max dz = 900
Mean dz = 16
RMS dz = 41.1217703899
100cm = 97.5536873409 percentile value of dz