ArcGIS Pro 3.0.2: The result of the “service area” of the network dataset appears to be weird in the zones with no roads network,

Question

In the screenshot below, the result of the “service area” of the network dataset based on the given facilities appears to be weird in the zones with no roads network. I was expecting the coverage to by as sketched in the second screenshot. The default length is taken as cost impedance.

What could be the explanation for this?

Melinda Morang · Accepted Answer

The Service Area polygon generation algorithm has various rules about when areas should be covered or uncovered, and these depend whether the area is fully surrounded by accessible roads and the various polygon geometry settings used in the analysis.  Try adjusting the polygon trim setting to a larger trim distance.  This will cover more area farther from the roads.

Scroll all the way down to the bottom of this page to read about polygon trim: https://pro.arcgis.com/en/pro-app/latest/help/analysis/networks/service-area-analysis-layer.htm#ESRI_SECTION1_D36A18B15D704F0DBA9B4C766A4A2719