Shptree notes

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shptree Processing Notes

(for the Benchmarking 2010 exercise)

shptree Depth

No depth parameter was used for the shptree command, which means the shptree code would determine the optimal depth. The determined depths were:

file depth
building 21
contour-0 16
contour-1 17
contour-2 17
contour-3 17
contour-4 17
contour-5 15
contour-6 17
contour-7 17
industry 17
motorway 10
point-labels-for-geometry 15
point-labels-no-geometry 18
ramp 14
road 14
settlement 16
track 16

Verifying the qix file

  • shptreetst utility was used to verify the integrity of qix file
  • you should see a message like:
 $ shptreetst contour-0.qix 
 This new LSB index supports a shapefile with 221671 shapes, 16 depth 
 shapes 0, node 4, -8.187613,36.166759,3.274251,43.666687 
 shapes 0, node 4, -8.187613,36.166759,-1.883588,40.291719 
 shapes 0, node 4, -8.187613,36.166759,-4.720399,38.435487 
 shapes 0, node 1, -8.187613,36.166759,-6.280646,37.414560 
 shapes 0, node 2, -7.329478,36.728269,-6.280646,37.414560 
 ... 
 
 read entire file now at quad box rec 20 file pos 1000
 using last read box as a search 
 result of rectangle search was 
   86554, 86580, 86586, 86598, 86638, 86641, 86642, 86643, 86660, 86667, 195862, 195895, 195901, 195903, 195926, 196873, 197711,

buildings.shp

  • shptreetst building.qix caused a Segmentation fault initially on our BenchmarkB Linux server (with 8GB RAM)
  • to solve this we...