Question

How do I specify additional connection nodes for custom shapes imported as SVG, by default only connection node is at the centre.

Answer 1

There are two ways to have edges connect at a position other than the node center:

1. Press and hold SHIFT, then start and and edge creation at the desired positions. (Both start and end position have to be inside nodes, though, otherwise the dragging the mouse will not be recognized as edge creation gesture.)
2. Click an existing edge, go to the properties view in yEd's lower right corner, and adjust "Source Port X", "Source Port Y", "Target Port X", and "Target Port Y" as desired. (With this approach it is possible to move theedge connection point outside the corresponding node.)