I have a polygon file with 90 adjacent polygons. I also have a lat/long point file that overlaps the entire surface of the polygon file (170,000 points). My problem is that working with all of the data at once is far too demanding and slows the project considerably. If I could have the individual polygons separated and have only the points that are intersecting with those polygons on those separated layers, I could work smoother as I wouldn't have to deal with the entire data set at once.

My first idea (which is still in progress) is to do a simple join attributes by location. I say it's still in progress because with 90 polygons and 170,000 points I have been looking at the rainbow loading wheel for a while...

Just wondering if this is the best option or if there's a better idea out there. I'd like to be able to work on one polygon at a time and also be able to interact with the points which are associated with that polygon.

QGIS on a Mac.

Thanks =)

  • Separating the polygons in separate files would mean that you would need to merge them back later right? Do you have your data in shapefile? I would try katahdin suggestion first. Install Postgresql\postgis and put your data there. With Postgis spatial index QGIS will decide better what to draw and won't care about the rest. Also, In QGIS you might want to set Scale dependent rendering for your layer, for instance to draw points only if you zoom to the level of one polygon. That will make rendering the full zoom faster. Commented May 14, 2013 at 8:18

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Importing the data into a PostgreSQL database would speed the process up considerably. You could use shp2pgsql from the command line, or load the data via QGIS's database tools.

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