curvature versus slope
  n = 2419571 
  X=0, Y = 44.57 +/- 33.76 
  Weighted least-squares fit:  Y = 54.5 + 0.906 X  + -0.00651 X**2 

slope versus dZ, curvature < 5
  n = 50316 
  X=0, Y = 5.03 +/- 2.58 
  Weighted least-squares fit:  Y = 4.8 + 0.136 X  + 0.00140 X**2 
     at X = 100, Y = 32.5 
     effective RMSE xy = 50.4 

slope versus dZ, curvature < 15
  n = 205338 
  X=0, Y = 5.37 +/- 3.13 
  Weighted least-squares fit:  Y = 4.8 + 0.138 X  + 0.00139 X**2 

curvature versus dZ, slope < 10
  n = 138471 
  X=0, Y = 5.84 +/- 3.04 
  Weighted least-squares fit:  Y = 5.7 + 0.091 X  + 0.00058 X**2 


Number of samples 2552697
Max dz = 900
Mean dz = 1277
RMS dz = 4428.94287613
100cm = 99.3956196133 percentile value of dz
Mean dz (curv<=5) = 395
RMS dz (curv<=5) = 2663.98967716