Calculate Service Area measuring from polygon boundary

[GeorgieCassar1]

Would like the ability to generate a service area measuring from the boundary of polygons instead of from a point.

For example we are mapping the walking distance from park boundaries along the surrounding road.network.  Doing this from a park centroid produces inaccurate results.

Ability to do this in both desktop and online apps too.

[JoeBorgione]

I think I understand what you are looking for, but I don't see how the actual logic would work; if you start a route from somewhere on a polygon's outer edge, how would/could you specify which edge and where along that edge?

[MelindaMorang]

Network Analyst fundamentally requires a point as the starting and ending location for an analysis. There simply is not a way to use a polygon without representing it somehow as a point (or multiple points).

The trick is to select your representative points in a clever way. You've already noted that the centroid isn't a good representation. That's definitely true for larger polygons, or irregularly-shaped ones.

You could choose points representing park entrances. You could chose points where nearby streets meet the park boundaries. You could choose polygon vertices.  You could space points every X meters along the park's boundary.

If you choose to represent the polygon with more than one point, you can combine the resulting Service Area polygons into a single feature by choosing the Merge option. This way the result gives you a single polygon that represents the area reachable within a time or distance limit from the park.