Service Area Polygon Not Reaching Full Cutoff Distance

Question

Hi everyone,

I'm working on a pedestrian network analysis in ArcGIS Pro using the Service Area tool to generate walkable catchments.

I’ve set the cutoff distance to 350 meters, and I'm using a custom pedestrian network dataset that has been preprocessed to remove Z-values and split at junctions. However, I noticed that the resulting service area polygons do not appear to extend the full 350 meters when measured along the network from the facility.

Here's what I’ve checked/tried so far:

* Cutoff is correctly set to 350 meters.
* The network is working as expected, with facilities snapped to it.
* I'm measuring distance along the visible road network.
* I used the “Split Line at Point” tool to prepare the edges, and the network dataset was created with both edge and junction sources.
* In the Add Locations tool, I ensured “Snap to Network” was checked.
* I’m using the default polygon generation settings (generalized polygons).

Despite this, when using the measure tool on the service area output, the distance from a facility to the polygon edge comes up short — well under 350 meters in some directions.

Has anyone else encountered this? Could this be due to the polygon generation method, lack of detailed polygon settings, or something else in the network definition?

Any help or clarification would be greatly appreciated!

Thanks,

Sara

SaraKhan1 · Answer

Hi, thanks for jumping in!

You're absolutely right - here’s some follow-up:

Screenshot:

I’ve attached a screenshot below showing:

* The facility location
* The resulting service area polygon (cutoff set to 350 meters)
* A measured line along the visible road network from the facility to the polygon edge showing significantly less than 350 meters (~250 m)

Coordinate System:

* The map frame and data are both in:
WGS 1984 UTM Zone 40
*  Units: meters

Additional Info:

* I'm using a custom pedestrian network dataset, based on cleaned and integrated roads
* Z-values were removed
* The network dataset uses a Length field (meters) as the impedance
* Facilities are snapped to the network using the import facilities tool

Let me know if another view or the raw outputs would help — I can share more detail. Appreciate your time!

Screenshot 2025-08-01 112643.png

Screenshot 2025-07-30 122011.png

PedestrianNetwork_Analysis.gdb (2).zip

DanPatterson · Answer

do you have a screen grab perhaps showing the perceived differences?

what is the coordinate system of the map and data?