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I have a large dataset that I want to perform spatial analysis on in QGIS.

Specifically, I want to perform a polygon intersection analysis between two polygon layers.

Given the size of the dataset this may take hours to complete.

Does the file type impact the performance of executing the spatial analysis i.e. will shapefiles take longer to execute than GeoJSON, or vice versa?

  • I think you should run a few tests on various sized datasets to see whether you can answer your own question. How long does QGIS take to run on 5-10% of your data in a shapefile? How long does QGIS take to run on 5-10% of your data in a GeoJSON? – PolyGeo Dec 13 '18 at 22:10
  • It's hard to imagine that a verbose text format could hope to compete with a binary format. You should add another binary format, file geodatabase to your evaluation; with an appropriate spatial reference, FGDB should be 30-40% smaller than shapefile. – Vince Dec 13 '18 at 23:00
  • @Vince thanks for your response. I'm new to the GIS world - which file is text format and which file is binary format? And are you saying the binary format should perform quicker? – csft306 Dec 15 '18 at 14:43
  • You should be able to determine which is which by opening the files in a text editor (just don't save). There are an infinite number of processes which could be named "spatial analysis", so there is no way to predict performance. You need to prototype the process with a representative sample in both formats, and then you'll know. – Vince Dec 15 '18 at 14:52

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