[Qgis-psc] (QGIS 2020 Grant Report) Use of FileGeodatabase spatial index in OpenFileGDB driver
even.rouault at spatialys.com
Mon Sep 28 13:29:02 PDT 2020
I want to report about the outcome of
"Use of FileGeodatabase spatial index in OpenFileGDB driver"
This work has been successfully completed into GDAL master (for upcoming GDAL 3.2) per
https://github.com/OSGeo/gdal/pull/2771 , and automatically benefits to QGIS when it uses
the OpenFileGDB driver.
Some figures on a version from of few years ago of the dataset at
https://data.linz.govt.nz/layer/50772-nz-primary-parcels/, featuring 2 484 646 polygons, 773
MB:"ogrinfo -spat 174.949909 -41.143842 175.684529 -40.594600 -al -so -noextent" (thus
counting the number of features intersecting the spatial filter), which returns 81 046
polygons, nows runs in 400 ms with GDAL 3.2dev and the OpenFileGDB driver, versus 6.7 s
before (full scan), vs 890 ms with the FileGDB driver (with FileGDB SDK 1.5).
All figures given with debug builds, and on a hot run (so with most pages cached by the OS).
Interactive display of this dataset in QGIS with the OpenFileGDB driver is as fluid as with the
FileGDB one. Comparing behaviour of OpenFileGDB and FileGDB drivers with strace shows
that they read a similar amount of data in the .spx file, which confirms it is uses correctly.
The filegdb reverse engineered specification was also updated in
Thanks to qgis.org grant program for making this improvement possible.
Spatialys - Geospatial professional services
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