Absolute-values in the legend

[Brieden]

For the visualization of scalar values in a spatial grid, we use the radii of circle markers. We have replaced a linear mapping of values toward radii with a logarithmic mapping to cover the highly skewed distribution of values. This makes reading absolute values on the map difficult; the relative comparability of neighboring values is retained. Furthermore, reading absolute values is cumbersome, as the circle diameters in the map change with the zoom level but not in the legend. In the interactive map, absolute values can be displayed using tooltips, which no longer works with an exported map view (PNG).
How can both use cases be implemented in a user-friendly manner?