curvature versus slope
  n = 2364039 
  X=0, Y = 7.61 +/- 4.81 
  Weighted least-squares fit:  Y = 6.2 + 4.871 X  + -0.05344 X**2 

slope versus dZ, curvature < 5
  n = 1327998 
  X=0, Y = 8.17 +/- 5.40 
  Weighted least-squares fit:  Y = 13.4 + 0.393 X  + -0.00031 X**2 
     at X = 100, Y = 49.6 
     effective RMSE xy = 75.0 

slope versus dZ, curvature < 15
  n = 2082450 
  X=0, Y = 8.14 +/- 5.33 
  Weighted least-squares fit:  Y = 13.7 + 0.434 X  + -0.00034 X**2 

curvature versus dZ, slope < 10
  n = 1787652 
  X=0, Y = 14.80 +/- 9.42 
  Weighted least-squares fit:  Y = 14.4 + 1.881 X  + -0.05726 X**2 


Number of samples 2389918
Max dz = 900
Mean dz = 17
RMS dz = 31.5753068077
100cm = 98.8266124612 percentile value of dz