Geoskill: Road Accessibility Analysis

Compute shortest paths, isochrones, OD matrices, and facility service coverage from OSM or user-provided road networks. Supports drive/walk/cycle modes, road closures, and population coverage analysis. Use when the user needs travel-time analysis, service area delineation, or road network criticality assessment.

Road Accessibility Analysis

Performs network analysis on road networks to compute shortest paths, isochrones (service areas), origin-destination matrices, facility coverage, and road closure impact scenarios.

Trigger

Use when the user wants to:

• Compute shortest paths or travel times on road networks
• Generate isochrones / service areas from facilities
• Build OD matrices between origins and destinations
• Assess facility service coverage (hospitals, schools, etc.)
• Simulate road closure / disruption scenarios
• Identify critical edges whose removal degrades accessibility

CLI Usage

bash

# Shortest path between two points
python scripts/road_accessibility_analysis.py --network roads.geojson \
    --origins origins.geojson --destinations dest.geojson --mode drive

# Isochrone from facilities
python scripts/road_accessibility_analysis.py --network roads.geojson \
    --origins facilities.geojson --time-limit 15 30 60 --mode walk

# OD matrix
python scripts/road_accessibility_analysis.py --network roads.geojson \
    --origins origins.geojson --destinations dest.geojson --mode cycle

# With road closures
python scripts/road_accessibility_analysis.py --network roads.geojson \
    --origins origins.geojson --destinations dest.geojson \
    --closures closed_roads.geojson --mode drive

# With population coverage
python scripts/road_accessibility_analysis.py --network roads.geojson \
    --origins hospitals.geojson --time-limit 30 --mode drive \
    --population-raster pop.tif

数据下载

本 skill 可自动从公开数据源下载路网（无需预先准备数据）:

bash

# OSM 路网 + MPC DEM (cop-dem-glo-30) 自动下载
python scripts/road_accessibility_analysis.py \
    --bbox 116.30,39.85,116.45,39.95 \
    --date-range 2024-06-01,2024-06-30 \
    --output-dir ./raa-auto

# 或用 AOI 多边形文件
python scripts/road_accessibility_analysis.py \
    --aoi-file aoi.geojson --date-range 2024-06-01,2024-06-30 \
    --output-dir ./raa-auto

下载的内容:

• OSM 道路 (highway 要素) — 主输入，替换 --network
• Copernicus DEM GLO-30 (cop-dem-glo-30) — 辅输入，写入 downloaded/

下载元数据（data_source, fetched_at, osm_features, dem_path 等）会写入 output-manifest.json。

Parameters

Parameter	Required	Default	Description
--network	Yes	—	Road network (GeoJSON/Shapefile, LineString features)
--origins	No	—	Origin points (GeoJSON, Point features)
--destinations	No	—	Destination points (GeoJSON, Point features)
--mode	No	drive	Travel mode: drive, walk, cycle
--time-limit	No	30	Time threshold(s) in minutes for isochrones
--closures	No	—	Closed road segments (GeoJSON, LineString features)
--population-raster	No	—	Population raster for coverage analysis (GeoTIFF)
--output-dir	No	raa-output	Output directory
--speed-file	No	—	JSON file with custom speed per road type

Output

File	Description
routes.geojson	Shortest path routes (LineString features)
service_areas.geojson	Isochrone polygons per origin
od_matrix.csv	Origin-destination travel time/cost matrix
unserved_population.tif	Raster of population not covered by service areas
critical_edges.geojson	Edges whose removal most degrades accessibility
output-manifest.json	Machine-readable manifest

Exit Codes

Code	Meaning
0	Success
2	Argument error
3	Dependency missing
6	Validation error
7	Processing failure