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In QGIS: My data lists individuals only by zip code, not a more specific location. Those individuals are one of three categories. I have successfully completed a one-to-many join so that the attribute table for the zip code shapefile now has multiple lines for some of the zip codes. Each line represents a separate individual and a designation for his/her category.

My goal: I want the map for each zip code to show a marker for each individual in the attribute table. If there are five individuals for a zip code, I want the map to show five markers, each one potentially different based upon the individual's category. Right now, if a zip code has 5 individuals, my map shows only one individual as a centoid -- and hides the other 4.

How can I make my map show multiple markers if there are multiple individuals in the zip code?

Matthew
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  • Check this: https://gis.stackexchange.com/q/16830 – Taras Nov 06 '21 at 21:07
  • Thank you, Taras. That link led me to eventually find "Random points IN polygons" in the Processing Toolbar of QGIS 3.20. (Note: this is different than the "Random points INSIDE polygons" option.) I was able to create a map showing multiple markers, each representing one individual -- and showing multiple individuals inside each polygon (zip code). So progress! But the problem is that those points truly are randomly positioned. I would like them clustered in the middle of the polygon, not spread out on the edges. I will post a screen shot if the moderators tell me how. Any suggestions? – Matthew Nov 08 '21 at 21:08
  • Have a look at the point displacement renderer it should do the trick – J.R Nov 08 '21 at 22:29
  • Thank you for the suggestion. I tried running Points Displacement from the Processing Toolbox. I set the Minimum Distance to Other Points and the Displacement Distance at 0.000010 degrees (lowest possible). But the points remained in their "random" locations from the previous run, some along the polygon borders (even if it was the only point in the polygon). So the points are still not centered. Thank you for the suggestion, though. – Matthew Nov 08 '21 at 23:10
  • @Matthew my suggestion was to let all your point at the polygon centroid (so supperposed point) then use the Point Displacement renderer (in the layer styling panel) to display all your point... – J.R Nov 10 '21 at 09:51
  • Thank you for clarifying. I deleted the Random Points layer, then tried to run Points Displacement on my basic layer, which has the overlapping centoid points. I could not find Point Displacement in the "layer styling panel" (as you recommended), so I ran Points Displacement from the Processing Toolbar, and received the following error message: "MultiPolygon geometry cannot be converted to a point. Only Point types are permitted." My layer consists of zip code polygons, with multiple centoids that now overlap. Thank you for any help. – Matthew Nov 10 '21 at 20:16

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