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I am trying to count points within polygons (311 calls by Census tract). Both shapefiles are EPSG:4326, and I've done define projection just to double-check.

Every time I run "Join attributes by location (summary)" all values come back NULL. If not the projection, what else can cause this, or, if it is the projection, what else can I do to check?

  • can you post some screenshots or something to be sure you assigned the right things?
    – PieterB
    Apr 19, 2019 at 11:16
  • May be you uncheked PREDICATE or trying to Join layers in incorrect order (target and join) ?
    – Sergey N
    Apr 19, 2019 at 11:22
  • Just added screenshots. I noticed that the code says 'SUMMARIES' : [0] } even though it shows I selected an element. Maybe that's it?
    – Rosalie
    Apr 19, 2019 at 11:28
  • Update: I tried using a different summary measure 'Unique' instead of Count, and it returned all 1s, which is accurate (the field has only one value). So why can it recognize that but not count?
    – Rosalie
    Apr 19, 2019 at 14:34

2 Answers 2


I needed to use both intersect and within. Even though all the points were within a polygon zoomed in far enough, it wasn't capturing them for some reason.

  • 2
    I tested on Windows with QGIS 3.6.1, and it made no difference whether I chose "within" or "intersect" for the geometry predicate. It looks you're on a Mac, and for a while QGIS had a number of Mac-specific bugs. I think you should report this as a bug at issues.qgis.org.
    – csk
    Apr 19, 2019 at 18:19

Did you check your columns that need calculation are set as int or float type? In my case, I got NULL because all the columns that I wanted to get calculated summary were string types, so I changed its data types and it worked.

  • Good point. In this case I think polygons can't be within points. But if you can't make some maths on strings seems ok to me. Nov 14, 2022 at 2:12

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