The following statistics about the block diagram of your VI and its structures and wires appear in the VI Metrics dialog box when you select the Diagram checkbox:
DiagramsNumber of block diagrams. Each VI has a single top-level block diagram. In addition, it has one subdiagram for each loop or structure.
Maximum diagram depthDeepest nesting level of block diagrams in a VI. If your VI has no structures, it has a depth of 0.
Diagram widthWidth of the block diagram in pixels.
Diagram heightHeight of the block diagram in pixels.
Wire sourcesMeasures the total number of sources in your VI. Each wire has a single source, but it can branch to multiple destinations. If a wire enters or exits a structure, the tunnel it passes through is considered to be a new source.