curvature versus slope
  n = 195529 
  X=0, Y = 20.91 +/- 17.11 
  Weighted least-squares fit:  Y = 36.6 + 2.938 X  + -0.03213 X**2 

slope versus dZ, curvature < 5
  n = 56139 
  X=0, Y = 5.51 +/- 4.40 
  Weighted least-squares fit:  Y = 7.1 + 0.191 X  + 0.00078 X**2 
     at X = 100, Y = 34.0 
     effective RMSE xy = 52.2 

slope versus dZ, curvature < 15
  n = 89504 
  X=0, Y = 5.51 +/- 4.40 
  Weighted least-squares fit:  Y = 7.2 + 0.229 X  + 0.00081 X**2 

curvature versus dZ, slope < 10
  n = 43174 
  X=0, Y = 7.81 +/- 4.66 
  Weighted least-squares fit:  Y = 6.8 + 1.745 X  + -0.01143 X**2 


Number of samples 198529
Max dz = 900
Mean dz = 27
RMS dz = 55.8927544499
100cm = 94.9327302308 percentile value of dz