bluegreencity-ki

Construction Sites Criterion

Overview

The construction_sites criterion evaluates drought risk from proximity to active road construction sites (OSM highway=construction). Construction works damage roots, compact the soil, alter the local water regime and often reduce watering access — temporary but significant stressors for nearby street trees (issue #139).

The criterion is currently configured with weight 0.0: it contributes extras and the ML feature construction_dist_m to the AutoGluon training dataset, but not to the weighted total score (pending weight recalibration).

Implementation

Location

• Module: bluegreencity_ki/criteria/construction_sites.py
• Test: tests/test_subway_construction.py

Data Source

• OpenStreetMap ways tagged highway=construction, fetched via osmnx (Overpass fallback)
• Deliberately NOT cached: construction sites are temporary, so the data is fetched fresh from the Overpass API on every pipeline run (explicit requirement of issue #139)
• For Hannover (2026-07 snapshot): ~96 active construction ways

How It Works

1. Fetch: fetch_osm_construction() queries OSM for highway=construction line features within the configured bbox (no cache).
2. Nearest distance: sjoin_nearest computes the distance from each tree to the nearest construction way.
3. Distance breaks: The distance is mapped to a risk score via configurable breaks.

Scoring Logic

distance ≤ 25 m  → 0.7   (within the construction influence zone)
distance > 25 m  → 0.1   (no influence)

• No active construction sites in the bbox: all trees receive the lowest-risk score (0.1).
• Fetch failure (network/Overpass error): all trees receive the neutral score, meta.status = "no_data".

Configuration

inputs:
  osm_construction:
    bbox_wgs84: [9.60, 52.30, 9.92, 52.46]
    # deliberately no cache_path — temporary data, fetched fresh every run

criteria:
  - name: "construction_sites"
    weight: 0.0
    params:
      distance_breaks: [25]
      distance_scores: [0.7, 0.1]

Parameters

Parameter	Type	Default	Description
distance_breaks	list[float]	[25]	Distance thresholds in metres
distance_scores	list[float]	[0.7, 0.1]	Risk score per class (one more than breaks)

Output Fields

1. construction_sites_risk — risk score (0–1)
2. construction_dist_m — distance to the nearest construction way in metres (ML feature)

Known Limitations

1. Weight 0.0 until weights are recalibrated.
2. Line features only: construction areas (landuse=construction) are not evaluated; road construction is the dominant stressor for street trees.
3. Temporal validity: the score reflects the OSM state at pipeline runtime; historical training data cannot reproduce past construction sites (relevant caveat for the ML feature).
4. OSM mapping lag: short-lived construction sites may be missing or outdated in OSM.

Changelog

2026-07-22: Initial Implementation (#139)

• Uncached OSM fetch (osmnx + Overpass fallback) — fresh data every run
• Distance-break scoring, construction_dist_m as AutoGluon feature

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Author: BlueGreenCity-KI Team Last Updated: 2026-07-22