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This repository has been archived by the owner on Jul 24, 2021. It is now read-only.
Reporter: tms13 [Submitted to the original trac issue database at 8.21am, Wednesday, 5th May 2010]
The current implementation of shapefile reading has the following issues:
Coincident nodes are not shared between features
Polygons with holes are not converted to multipolygon relations
Projection is done one node at a time, rather than a geometry at a time (x2 performance hit(*))
(*) I'm guessing that the GDAL library can use SIMD instructions when doing bulk transforms, which might explain this.
My patch is tested and ready to apply.
Note that the Ordnance Survey "VectorMap District" NaturalFeature_Area.shp tiles have lots of 'Custom Landform' polygons with holes, so performance can be improved by generating a more specific file using ogr2ogr to crop or select features. It may be an idea to somehow allow the user to specifiy what feature types should be imported...
The text was updated successfully, but these errors were encountered:
Author: Koying [Added to the original trac issue at 1.11pm, Wednesday, 5th May 2010]
Please go ahead. If you are sure of your stuff, you don't have to go thru trac/patch...
It's not like the trunk is supposed to be bulletproof ;-)
Small trick if you are not aware:
If you put something like "(fixes #nnnn)", with nnnn being a trac ticket number, in you commit message, the ticket will be closed when you commit, with a back reference to the changeset.
Reporter: tms13
[Submitted to the original trac issue database at 8.21am, Wednesday, 5th May 2010]
The current implementation of shapefile reading has the following issues:
(*) I'm guessing that the GDAL library can use SIMD instructions when doing bulk transforms, which might explain this.
My patch is tested and ready to apply.
Note that the Ordnance Survey "VectorMap District" NaturalFeature_Area.shp tiles have lots of 'Custom Landform' polygons with holes, so performance can be improved by generating a more specific file using ogr2ogr to crop or select features. It may be an idea to somehow allow the user to specifiy what feature types should be imported...
The text was updated successfully, but these errors were encountered: