Selection.Join Method (Visio)
Creates a new shape by joining selected shapes.
Calling the Join method is equivalent to clicking Join in the Microsoft Visio user interface (click Operations in the Shape Design group on the Developer tab). The new shape inherits the text and formatting of the first selected shape and is the topmost shape in its container—the nth shape in the Shapes collection of its containing shape, where n = Count.
The original shapes are deleted and no shapes are selected when the operation is complete.
The Join method and the Combine method are similar but differ in the following ways:
Join coalesces abutting line and curve segments in the original shapes into a single Geometry section in the resulting shape.
Combine produces a shape that has one Geometry section for each original shape. The resulting shape has holes in regions where the original shapes overlapped.
You might want to join shapes after importing a non-Visio drawing in which apparent polylines are represented by many independent shapes, each possessing a single line or curve segment. By joining the shapes that constitute a polyline in such a drawing, you can replace many single-segment shapes with one multiple-segment shape.