Fire Zones Review Map — Methodology
Objective
Delineate a clear, defensible first-due response zone for each of
Knightdale's four fire stations (Knightdale #1–#4), so that
every property and every road segment has one unambiguous responding
station. This map shows the proposed zones and the supporting data used to
build them.
What you're looking at
- Station Zones — the four proposed response areas, one color per station.
- Assigned Segments (toggle on) — the street network colored by the station each segment was assigned to; the backbone of the zones.
- Classified Parcels (toggle on) — all 18,269 parcels, each assigned to a station.
- Fire Stations — station locations shown for reference.
How the zones are built
-
Anchor each station to the road network.
A station building doesn't sit exactly on a road centerline, so each station is
"snapped" to the nearest network feature before any routing is done. This
guarantees travel costs are measured from a real point on the network.
-
Assign every street segment to its nearest station (by travel cost).
Each of the 5,960 street segments is allocated to the station with the lowest
network travel cost from the segment to the station. This produces a true
first-due street coverage that follows how apparatus actually
drive, rather than a geometric "as-the-crow-flies" split.
-
Classify parcels to satisfy fire-service requirements.
Response standards and accreditation are property- and address-based
— runs are dispatched to structures, and coverage is evaluated per built-upon
property (e.g., response-time benchmarks and insurance/PPC-style
distance-to-property measures). A boundary polygon by itself can cut through a
parcel or leave ambiguous slivers, which is unacceptable for run cards and
automatic/mutual-aid agreements. Classifying all 18,269 parcels directly ensures
each property has exactly one first-due station, with no split or
unassigned addresses.
-
Classify the right-of-way (ROW) separately from parcels.
Roads are public right-of-way, not parcels, so they aren't covered by parcel
polygons. The assigned street segments carry the ROW classification
— each road segment is allocated to a station independently. Combining parcel
classification (private land) with segment classification (public ROW) gives
complete, gap-free coverage of both addresses and the roadways
between them.
-
Snap zone boundaries to intersections.
Because the assigned segments are network edges that begin and end at
intersections, the zone boundaries are derived from each station's set of assigned
segments and break at intersections rather than mid-block. The
resulting
station_zones are built from a mixed source (parcels + ROW
segments) so the lines follow real streets and intersections — boundaries crews
can describe operationally ("everything north of Main, east of First") instead of
arbitrary geometry.
What we'd like you to confirm
- The four zone boundaries look right at the edges, especially around shared intersections.
- Parcels near boundaries are assigned to the station you'd expect.
- Any known coverage agreements (automatic/mutual aid) that should override nearest-station logic.