Creating different size service areas for single facility using ArcGIS Network Analyst?

Question

When running NA Service Area analysis for a single point location (facility), I see a different service area polygon returned depending on whether Overlapping and Non-Overlapping polygons. For a single facility I would expect the same results back as there is no overlap likely to occur (for single extent of service area).

Is there a subtle difference in the processing which would mean even single facilities are processed differently in one or other approach?

Answer 1

I think I have found an answer to this - though not sure why trimming effectively increases service areas. By disabling the trimming in the options for the service area solution, the polygon returned is equal when Overlapping or Not Overlapping is selected.

http://support.esri.com/en/technical-article/000014632