While modifying some geometries in QGIS in my previous question Adjusting flow map styles in QGIS: Varying buffers' sizes I ended up with a huge confusion regarding the dimensions/units that Geometry Generator in QGIS works with.
For instance, I do have a point layer that responds to my visualization purposes, units are Millimeters.
Points are visualized with Graduated symbols using the following specifications. 6 groups, sizes from
But when I apply Map units the visualization aspect changes dramatically. Those points are visible only at large map scales and cannot be viewed at the same map scale that used for the image above. As I should, I am working with projected CRS, where units are Meters.
How to convert the dimensions into Units or Pixels to be able to deploy Geometry Generator on the next step and at the same time maintain the visualization aspect? How should I adjust the parameters of my points?
Because when I want to use this point layer in the Geometry Generator (i.e.
end_point()) I have to have Map Units. I require those aspects to adjust the place where lines between points should start and end.
difference( difference($geometry, buffer(start_point($geometry), CASE WHEN "From_Value" IS NOT NULL THEN scale_exp("From_Value"/ "From_Value"*2, @From_min, @From_max, 2, 12, 1) ELSE 0 END ) ), buffer(end_point($geometry), CASE WHEN "To_Value" IS NOT NULL THEN scale_exp("To_Value"/ "To_Value"*2, @To_min, @To_max, 2, 12, 1) ELSE 0 END) )
Am I correctly understand that Geometry Generator works only with Map Units, or?