curvature versus slope
  n = 653803 
  X=0, Y = 3.64 +/- 2.40 
  Weighted least-squares fit:  Y = 2.3 + 5.920 X  + -0.12082 X**2 

slope versus dZ, curvature < 5
  n = 525745 
  X=0, Y = 12.65 +/- 9.84 
  Weighted least-squares fit:  Y = 11.2 + 0.622 X  + -0.00056 X**2 
     at X = 100, Y = 67.8 
     effective RMSE xy = 105.0 

slope versus dZ, curvature < 15
  n = 623160 
  X=0, Y = 12.93 +/- 9.90 
  Weighted least-squares fit:  Y = 10.9 + 0.714 X  + -0.00124 X**2 

curvature versus dZ, slope < 10
  n = 610408 
  X=0, Y = 13.25 +/- 8.81 
  Weighted least-squares fit:  Y = 13.3 + 0.343 X  + 0.16958 X**2 


Number of samples 655015
Max dz = 200
Mean dz = 12
RMS dz = 17.2336879396
100cm = 99.7682495821 percentile value of dz