I'm trying to achieve this kind of labeling using QGIS. Apparently, it doesn't seem to be easily supported. Would you have an idea for a workaround ?
I managed to have circled text using "Diagrams", which it seems I can even place using an X and Y coordinate field ! But I have no idea on how to draw a line between the circle and the building... I have about 400 circles to place, and they could quite often change, so I can't rely on a manual method.
So here's what I've got using the plugin suggested :
Not bad at all!
I'm only struggling to put the number in the center of the circle. I see there are two fields : LblAlighH and a LblAlignV. Entering "center" in LblAlignH centers the number horizontally, but I tried "middle" or "center" in LblAlignV without anything happening... (in the image, I've entered center for LblAlignH in the one at the bottom)
The value "half" in the VAlign field seems to work fine.
To create the circles, I used line decorations in the Arrow_Label_XXX layer :
And here's the final result: