curvature versus slope
  n = 1439943 
  X=0, Y = 5.67 +/- 2.96 
  Weighted least-squares fit:  Y = 4.7 + 4.920 X  + -0.05190 X**2 

slope versus dZ, curvature < 5
  n = 1175571 
  X=0, Y = 261.02 +/- 133.05 
  Weighted least-squares fit:  Y = 301.0 + -5.154 X  + 0.02477 X**2 
     at X = 100, Y = 33.2 
     Bad fit. P2 = 0
slope versus dZ, curvature < 15
  n = 1387679 
  X=0, Y = 263.00 +/- 130.61 
  Weighted least-squares fit:  Y = 308.0 + -6.454 X  + 0.04001 X**2 

curvature versus dZ, slope < 10
  n = 1281864 
  X=0, Y = 271.96 +/- 114.15 
  Weighted least-squares fit:  Y = 271.7 + 2.205 X  + -0.33120 X**2 


Number of samples 1439955
Max dz = 900
Mean dz = 242
RMS dz = 268.23497162
100cm = 19.6291550778 percentile value of dz