curvature versus slope
  n = 1375408 
  X=0, Y = 27.60 +/- 23.59 
  Weighted least-squares fit:  Y = 69.4 + 1.390 X  + -0.01370 X**2 

slope versus dZ, curvature < 5
  n = 16013 

  Weighted least-squares fit:  Y = 63.6 + -0.131 X  + 0.00141 X**2 
     at X = 100, Y = 64.5 
     effective RMSE xy = 17.4 

slope versus dZ, curvature < 15
  n = 65607 

  Weighted least-squares fit:  Y = 63.2 + -0.106 X  + 0.00149 X**2 

curvature versus dZ, slope < 10
  n = 9257 
  X=0, Y = 60.98 +/- 46.35 
  Weighted least-squares fit:  Y = 61.8 + -0.490 X  + 0.04193 X**2 


Number of samples 1399625
Max dz = 900
Mean dz = 70
RMS dz = 93.8882314244
100cm = 75.7365722962 percentile value of dz