Open Catchment Accessibility Analyzer

Open Catchment & Accessibility Analyzer Analyze spatial accessibility around one or more locations by generating catchment areas and counting nearby services using OpenStreetMap (Overpass API). This Actor is designed for urban planning, transport analysis, public service accessibility studies, and research workflows. It supports multiple locations, multiple radii, structured outputs, and GIS-ready formats.

🚀 What this Actor does For each anchor location and catchment radius, the Actor:

1. Builds circular catchment areas (WGS84)
2. Fetches nearby services from OpenStreetMap (Overpass API)
3. Counts services per category inside each catchment
4. Produces: o Structured Dataset results o CSV / XLSX tables o GeoJSON files (catchments & services) o JSON summary outputs

🎯 Typical use cases • Walkability & accessibility analysis • Public transport & service coverage studies • Urban planning & zoning assessments • Retail & service density analysis • Academic & policy research • GIS preprocessing for QGIS / ArcGIS

📥 Input Minimal example { "anchors": [ { "id": "a1", "anchor_name": "Yerevan Center", "anchor_type": "origin", "lat": 40.1811, "lon": 44.5136 } ] }

Full input example { "studyName": "Berlin Accessibility Study",

"anchors": [ { "id": "a1", "anchor_name": "Alexanderplatz", "anchor_type": "origin", "lat": 52.5219, "lon": 13.4132 }, { "id": "a2", "anchor_name": "Potsdamer Platz", "anchor_type": "origin", "lat": 52.5096, "lon": 13.3750 } ], 🧪 Optional: “Full features” { "studyName": "Full Accessibility Study",

"anchors": [ { "anchor_name": "City Center", "anchor_type": "origin", "lat": 52.5200, "lon": 13.4050 } ],

"radiiMeters": [500, 1000, 2000],

"serviceCategories": [ "pharmacy", "school", "hospital", "supermarket", "public_transport_stop" ],

"maxResultsPerCategory": 2000,

"outputMode": "summary", "outputFormats": [ "dataset", "summaryJson", "csv", "xlsx", "geojson" ],

"includeGeometries": true }

"radiiMeters": [300, 800, 1500],

"serviceCategories": [ "pharmacy", "school", "supermarket", "public_transport_stop" ],

"outputMode": "summary",

"outputFormats": [ "dataset", "csv", "xlsx", "geojson", "summaryJson" ],

"includeGeometries": true, "maxResultsPerCategory": 1500 }

📌 Input fields reference Anchors (required) Each anchor represents a study location. Field Type Description id string Optional identifier anchor_name string Human-readable name anchor_type string e.g. origin, stop, facility lat number Latitude lon number Longitude

Catchment radii "radiiMeters": [300, 500, 1000] Multiple radii are supported; results are generated for each radius × anchor.

Service categories Simple (legacy) categories supported out of the box: • pharmacy • school • hospital • post_office • supermarket • public_transport_stop • businesses • business_retail • business_food • business_services • business_office You can also use curated categories via selectedCategoryIds if a catalog is configured.

Output mode "outputMode": "summary" • summary → one row per anchor × radius × category • raw → one row per individual service (POI) inside catchments

Output formats "outputFormats": ["dataset", "csv", "xlsx", "geojson", "summaryJson"] Format Description dataset Apify Dataset results csv Downloadable CSV xlsx Excel workbook geojson Catchments & service points summaryJson Aggregated JSON summary

📤 Output Dataset (Apify Dataset tab) Example record (summary mode): { "study_name": "Catchment study", "anchor_name": "Yerevan Center", "anchor_type": "origin", "radius_m": 500, "category_id": "pharmacy", "services_count": 16, "coverage_adequate": true }

CSV / XLSX Files are available: • Locally (during development): ./output/ • On Apify: Key-Value Store (downloadable) Examples: • catchment_results.csv • catchment_results.xlsx

GeoJSON • Catchment polygons • Service point layers Ready for QGIS / ArcGIS / Mapbox

🛠 Local development export APIFY_LOCAL_STORAGE_DIR="$(pwd)/apify_storage" python -m src.main Edit input at: apify_storage/key_value_stores/default/INPUT.json

⚠️ Notes & limitations • Uses Overpass API (rate-limited) • Circular (distance-based) catchments only (isochrones can be added later) • Best for small–to–medium study areas per run

🧭 Roadmap ideas • Time-based isochrones (walk / drive) • Address → coordinate geocoding • Accessibility scoring index • Population-weighted coverage • Batch processing from CSV inputs

👤 Author Developed by AdInfoSys Management Institute Specializing in transport planning, GIS analytics, and data-driven public-sector consulting.