curvature versus slope
  n = 864948 
  X=0, Y = 7.21 +/- 6.06 
  Weighted least-squares fit:  Y = 6.8 + 4.960 X  + -0.05733 X**2 

slope versus dZ, curvature < 5
  n = 479192 
  X=0, Y = 9.93 +/- 6.87 
  Weighted least-squares fit:  Y = 8.7 + 0.380 X  + 0.00006 X**2 
     at X = 100, Y = 47.3 
     effective RMSE xy = 73.0 

slope versus dZ, curvature < 15
  n = 741398 
  X=0, Y = 10.33 +/- 7.08 
  Weighted least-squares fit:  Y = 9.2 + 0.410 X  + 0.00001 X**2 

curvature versus dZ, slope < 10
  n = 651279 
  X=0, Y = 10.08 +/- 6.14 
  Weighted least-squares fit:  Y = 9.4 + 1.567 X  + 0.03643 X**2 


Number of samples 869840
Max dz = 900
Mean dz = 12
RMS dz = 25.1197133742
100cm = 99.3687344799 percentile value of dz