curvature versus slope
  n = 56961 
  X=0, Y = 51.97 +/- 39.46 
  Weighted least-squares fit:  Y = 74.7 + 1.148 X  + -0.01137 X**2 

slope versus dZ, curvature < 5
  n = 2043 

  Weighted least-squares fit:  Y = 121.5 + 0.506 X  + -0.00121 X**2 
     at X = 100, Y = 160.0 
     effective RMSE xy = 163.6 

slope versus dZ, curvature < 15
  n = 7267 

  Weighted least-squares fit:  Y = 124.9 + 0.237 X  + 0.00089 X**2 

curvature versus dZ, slope < 10
  n = 519 
  X=0, Y = 127.20 +/- 47.18 
  Weighted least-squares fit:  Y = 126.3 + -4.182 X  + 1.97567 X**2 


Number of samples 57143
Max dz = 900
Mean dz = 148
RMS dz = 256.92800548
100cm = 35.6036609908 percentile value of dz
Mean dz (curv<=5) = 135
RMS dz (curv<=5) = 213.447885911