[Qgis-user] how to make marker size related to values in column

[M.E.Dodd]

I would like to make point markers of varying sizes depending on their value i.e. if it has a value of 10 then it would have a larger marker than if it had a value of 1.  This seems to be sort of possible via new symbology>advanced>size scale field.  However it only allows the values themselves from the column not any transformation of them e.g. sqrt or log.  When producing this kind of map you often want to transform the numbers as they are often of much too large a range to show with a simple linear scale.
So then tried the attribute table and field calculator to produce some new fields with these transformed values and got caught up in how on earth to do it and it did not seem to have log anyway.  Will simply produce these transformed values in spreadsheet outside qgis and reimport them and give it another go, but perhaps something for the wish list is to make it easier to do these different sized markers and have different options for transformations as you often don't know what kind of transformation would be suitable until you see them on the map.


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