curvature versus slope
  n = 1311279 
  X=0, Y = 14.27 +/- 11.36 
  Weighted least-squares fit:  Y = 22.1 + 4.025 X  + -0.04526 X**2 

slope versus dZ, curvature < 5
  n = 418689 
  X=0, Y = 52.04 +/- 15.93 
  Weighted least-squares fit:  Y = 41.7 + -0.009 X  + 0.00182 X**2 
     at X = 100, Y = 59.1 
     effective RMSE xy = 65.7 

slope versus dZ, curvature < 15
  n = 746289 
  X=0, Y = 51.50 +/- 16.22 
  Weighted least-squares fit:  Y = 39.8 + 0.113 X  + 0.00067 X**2 

curvature versus dZ, slope < 10
  n = 362164 
  X=0, Y = 44.90 +/- 22.71 
  Weighted least-squares fit:  Y = 42.4 + -1.216 X  + 0.08602 X**2 


Number of samples 1322378
Max dz = 900
Mean dz = 39
RMS dz = 53.2447180479
100cm = 96.6367407806 percentile value of dz