QGIS » QGIS Application

shift_svg_symbol_anchor_bottom.pdf:

you can see a different size of symbol (ok the “area issue”, but why a different behaviour if you set the same dimension value in style window or in data properties?)

The reason for area mode is that if an attribute value is used for symbol size, it is usually used to visualize some quantitative phenomenon and human perception considers as magnitude of a symbol its area not its diameter.

The area mode makes only sense for data defined dimension, where size of each symbol is different. If a constant dimension value (defined in standard style widget, not data defined) is used, area mode makes no sense and so it is only applied to data defined dimension.

The default area mode may be changed to diameter mode in Style tab -> Advanced -> Size scale field -> Scale area / Scale diameter.

and a “shift” of the symbol from his insertion point, like

scaling origin wasn’t symbol bottom.

This is a bug.

The same or similar problem was also with simple marker and ellipse. Symbol layers were simply ignoring data defined size in offset calculation.

It should be fixed for all.

There were two problems with data defined anchor with SVG and ellipse symbol layers:

• data defined values were ignored (expression not retrieved before rendering)

• the keywords in help were localized while expression evaluation was not

I have disabled the translation because I am convinced that such a keywords should not be localized to keep data and projects portability. OTOH, some polygon fill parameters do support translation, so I am going to raise this question on mailing list.