curvature versus slope
  n = 77112 
  X=0, Y = 11.61 +/- 9.86 
  Weighted least-squares fit:  Y = 21.5 + 4.047 X  + -0.04658 X**2 

slope versus dZ, curvature < 5
  n = 33586 
  X=0, Y = 10.50 +/- 4.28 
  Weighted least-squares fit:  Y = 7.2 + 0.286 X  + -0.00032 X**2 
     at X = 100, Y = 32.6 
     effective RMSE xy = 50.0 

slope versus dZ, curvature < 15
  n = 46006 
  X=0, Y = 10.50 +/- 4.28 
  Weighted least-squares fit:  Y = 7.3 + 0.335 X  + 0.00001 X**2 

curvature versus dZ, slope < 10
  n = 31859 
  X=0, Y = 8.33 +/- 4.76 
  Weighted least-squares fit:  Y = 7.6 + 1.800 X  + -0.08704 X**2 


Number of samples 78580
Max dz = 900
Mean dz = 21
RMS dz = 40.2367990775
100cm = 96.5958259099 percentile value of dz