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I have been trying to make flow maps to show social relationships between people geographically based on baptismal records. I have successfully made maps using https://anitagraser.com/2019/05/04/flow-maps-in-qgis-no-plugins-needed/ which shows the relationships between two separate points. But what my map is lacking is representations of non-movement.

So, if a person was baptized in the same location their parents and godparents lived. I had previously used Gephi and the representation there was a weighted circle around the point and I would like to do something like that, so I can weight them (hopefully) the same way I weighted the lines and give a more accurate portrayal of the social networks in a geographic framework. Any suggestions?

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Taras
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Catherine LaVoy
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  • Can you include a screenshot of how it should look like? And: circles weightwd by what? An attribute value? – Babel Dec 28 '20 at 09:59
  • I added a picture my current map above. Tried to add the Gephi image and excel worksheet, but not sure it worked. Basically, the arrows are weighted by the frequency of the connections, but there is nothing that shows the weight of the connections to the town the baptism takes place in. So, if town 105 has 35 connections to town 105, there is nothing on the map to show that. I would ideally like to make a circle with the same scale weight/size as the arrows around the town to make the connection (how insular the town is) apparent to the viewer. – Catherine LaVoy Dec 28 '20 at 13:40
  • Screen shot of Excel spereadsheet data: https://drive.google.com/file/d/15sSnb3orGU9LHqJIm7Mk2OgOaC_aeN8W/view?usp=sharing – Catherine LaVoy Dec 28 '20 at 13:44
  • Screen shot of Gephi analysis: https://drive.google.com/file/d/1GzfdvDKS8xV2BoEjJ1buJ8YcvJi8NNk9/view?usp=sharing – Catherine LaVoy Dec 28 '20 at 13:44

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You can represent these points using a data driven size. To the right of the size field for the points with no movement involved, click on data driven override, select assistant. In the opening panel, select an attribute field (ar build an expression) for the value to weight the size of your circles.

Below, click the two arrows to load min/max values, than below set min/max size of the circles. You can see in the map canvas that circles will now have varying sizes, based on my Weight field (I used transparent fill color to just draw an outer ring).

You can apply this method for almost every styling element (line thickness, color etc.).

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See also Manually adding centroids to arrows in Virtual Layers in QGIS for a different approach (arrows in a loop like circle that start and come back to the same point) - however, not the best way to represent that, in my opinion.

Babel
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