curvature versus slope
  n = 74337 
  X=0, Y = 61.09 +/- 19.10 
  Weighted least-squares fit:  Y = 67.9 + 1.490 X  + -0.01583 X**2 

slope versus dZ, curvature < 5
  n = 23248 

  Weighted least-squares fit:  Y = 18.2 + 0.197 X  + 0.00029 X**2 
     at X = 100, Y = 40.9 
     effective RMSE xy = 57.4 

slope versus dZ, curvature < 15
  n = 45730 

  Weighted least-squares fit:  Y = 22.6 + 0.075 X  + 0.00155 X**2 

curvature versus dZ, slope < 10
  n = 129 
  X=0, Y = 15.98 +/- 9.89 
  Weighted least-squares fit:  Y = 21.6 + 3.448 X  + -0.37156 X**2 


Number of samples 74779
Max dz = 900
Mean dz = 46
RMS dz = 153.554550568
100cm = 92.9472178018 percentile value of dz