Walkthrough — Parcels

Promise: edit an attribute in QGIS → Ctrl+S → the GISPulse rule fires and reclassifies the parcel's buildings. No GIS-client plugin needed.

What you'll see

A cadastral parcels layer plus a walking isochrone layer (500/750/1000 m). On every change to a parcel, GISPulse re-evaluates which buildings fall in which accessibility ring and writes the result into the accessibility_tier attribute.

Before	After save
accessibility_tier empty or stale on the buildings of the parcel you just edited	All buildings up to date: tier_500m, tier_750m, tier_1000m, or out_of_range

Prerequisites

• QGIS ≥ 3.28
• gispulse ≥ 1.5.1 (pipx install gispulse)
• The demo pack: gispulse examples fetch parcels

Setup (~1 min)

# 1. Install the change-log + SQLite triggers on the demo GPKG
gispulse track install ~/.gispulse/examples/parcels/parcels.gpkg

# 2. Start the watch loop (leave it running in a terminal)
gispulse triggers watch \
  --rules ~/.gispulse/examples/parcels/triggers.yaml \
  --dataset ~/.gispulse/examples/parcels/parcels.gpkg

The terminal continuously prints:

[info] watching parcels.gpkg for change-log entries
[info] 0 pending events

The scenario in 3 steps

1. Open the layer in QGIS

Layer → Add Layer → Vector → ~/.gispulse/examples/parcels/parcels.gpkg

Pick parcels, then also load buildings and isochrones from the same GeoPackage.

2. Edit a parcel

Toggle edit mode (Ctrl+E), redraw the boundary of a parcel sitting near an isochrone ring, then save (Ctrl+S). That's it.

3. The trigger fires

The terminal immediately shows:

[info] dml.changed parcels fid=42
[info] rule:classify_buildings_in_isochrones triggered
[info]   → 6 buildings reclassified
[info]   → 2 moved tier_750m → tier_500m
[info]   → 4 unchanged
[info] commit ok in 87 ms

Re-open the buildings attribute table in QGIS (F6) — the accessibility_tier column is up to date.

See the same scenario online

The demo portal runs the very same rule on the same dataset, with nothing to install:

🔗 Try it on try.gispulse.dev/parcels

Pick the isochrone radius (500/750/1000 m), click Run trigger, and the portal shows the reclassified buildings on the map. Same rule, same dataset, same engine.

Expected portal output

Events panel (/explorer):

2026-05-02T14:32:11Z  classify_buildings_in_isochrones  parcels#42  ok 87ms
2026-05-02T14:32:11Z  dml.changed                       parcels    fid=42

What's next?

• The sister walkthrough Isochrone shows how to recompute the rings when the parcel itself changes shape.
• Audit traces every modification and exports a CSV for compliance.
• The CLI ↔ Portal matrix lists every public capability exposed on both sides of the same source of truth.