curvature versus slope
  n = 554628 
  X=0, Y = 24.70 +/- 18.62 
  Weighted least-squares fit:  Y = 42.1 + 2.918 X  + -0.03289 X**2 

slope versus dZ, curvature < 5
  n = 179290 
  X=0, Y = 5.80 +/- 3.74 
  Weighted least-squares fit:  Y = 16.6 + -0.272 X  + 0.00453 X**2 
     at X = 100, Y = 34.7 
     effective RMSE xy = 47.8 

slope versus dZ, curvature < 15
  n = 236213 
  X=0, Y = 5.80 +/- 3.74 
  Weighted least-squares fit:  Y = 16.0 + -0.089 X  + 0.00417 X**2 

curvature versus dZ, slope < 10
  n = 91003 
  X=0, Y = 14.80 +/- 11.99 
  Weighted least-squares fit:  Y = 15.7 + 3.005 X  + -0.16145 X**2 


Number of samples 557717
Max dz = 900
Mean dz = 38
RMS dz = 69.1158447825
100cm = 90.4284789598 percentile value of dz