I'm performing some basic spatial analyses on a large database of traffic injuries in California between 2003 - 2011. Because the dataset is large (nearly 1 GB of points), I'd like to first cut it down to a specific geographic region using a spatial query, but I find that QGIS consistently freezes and hangs if I try to use a spatial query or filter the layer.
What are some ways I can work with this dataset? Are there more efficient data formats I can use?
Load the data into SpatiaLite in QGIS... best way is to create a new SpatiaLite database via the right-click GUI in the browser window, then simply drag and drop your shapefile onto the SpatiaLite database you just created.
From there you have all the power of SpatiaLite at your disposal, including SQL and SQL Spatial functions, which are a way more intuitive way to work with this kind of data.
Some more documentation can be found here, and there's the SpatiaLite manager plugin.
I would suggest to export the shapefile(s) to SQlite or FileGDB (which should perform better in QGIS). You can either do this in QGIS GUI (right click on layer a select Save As), or use OSGeo4WShell to covert using ogr2ogr, e.g. command:
ogr2ogr -f "FileGDB" C:/Temp/myshp.shp C:/Temp/test.gdb
OR
ogr2ogr -f "SQLite" C:/Temp/myshp.shp C:/Temp/test.sqlite
*Note, if you are editing the data I would suggest SQLite, since you cannot edit FileGDB in QGIS, however either option should suffice for viewing.
Perhaps use GRASS to Clip the area? You could run this in command prompt, and it wouldn't require loading the dataset with QGIS first.
