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My first query on here. I'm using QGIS. I've created a gridded map by counting points in each grid:grid map

This was generated by counting the number of observation points per grid(polygon). The attribute table in the observation (polygon) layer looks like this: attribute table of point layer But I now wish to create a similar gridded map, but instead of just counting the number of points within each grid, I wish to count the contribution of each author_id within each grid and add a column which shows the highest contributor within each grid.

Is this doable?

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    – underdark ♦
    Nov 23, 2017 at 17:52
  • Welcome to GIS SE. As a new user, please take the Tour. Unfortunately, the answer to nearly every "Is this possible?" question is "Yes", so you'll get a better answer if you actually try to solve the problem, and ask for help if you run into a problem.
    – Vince
    Nov 23, 2017 at 17:53

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Yes. Instead of using the "Count points in polygon" tool just use the "Join attributes by location" tool.

Found from Vector> Data Management Tools> Join attributes by location

In the option, be sure to set "Attribute summary" to: "Take summary of intersecting features"

If you only want max, you can set "Statistics for summary" to: max

For QGIS 3.14+ this is now done with the Join Attributes by Location (Summary) from:

Processing Toolbox (Accessed from Processing> Toolbox)> Vector general> Join attributes by location (summary)

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  • At 3.18, I do not see the "Attribute summary" option or the "Statistics for summary" option. Have they been moved elsewhere?
    – Stu Smith
    Mar 2, 2021 at 18:41
  • I wouldn't use 3.18 right now. It has a lot of bugs.
    – HeikkiVesanto
    Mar 3, 2021 at 9:52
  • Right you are! I'm now at LTR 3.16.4. However, I still don't see "Attribute summary" or Statistics for summary". Can you post a screenshot, along with the QGIS version?
    – Stu Smith
    Mar 3, 2021 at 17:05
  • It can now be done with the Join attributes by location (summary) tool, I updated the answer.
    – HeikkiVesanto
    Mar 3, 2021 at 22:17

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