Category Expansion

The step-by-step expansion to additional data categories is central to scaling p2d2.

Starting Point: Cemeteries

Why cemeteries as pilot project?

• Manageable complexity: Clearly defined geometries
• Administrative relevance: Cities must manage cemeteries
• OSM gap: Cemeteries are often incomplete in OSM
• Low change rate: Cemeteries rarely change

Successes:

• 25 cemeteries in Cologne recorded
• Geometries corrected and transferred to OSM
• Attributes added (opening hours, contact)

Categories Roadmap

Phase 1: Green Spaces (2025)

Flower Beds

• Similar geometry to cemeteries (polygons)
• Higher change rate (seasonal)
• Administrative relevance: Green space departments

Parks and Green Areas

• Larger areas
• More attributes (playgrounds, benches, paths)

Phase 2: Transportation Infrastructure (2026)

Cycle Paths

• LineStrings instead of polygons
• Attributes: Width, surface, lighting
• OSM category: cycleway

Parking Lots

• Points or polygons
• Attributes: Number of spaces, parking fees
• Dynamic data: Occupancy (future)

Phase 3: Cultural Heritage (2026)

Monuments

• Points with detailed descriptions
• WikiData integration particularly relevant
• Photos and historical information

Cultural Sites

• Theaters, museums, galleries
• Opening hours, events

Phase 4: Social Infrastructure (2027)

Playgrounds

• Polygons with equipment attributes
• Safety inspections as temporal dimension

Public Toilets

• Points with accessibility information
• Opening hours

Category Requirements

Technical

Category	Geometry	Attributes	Change Rate	Complexity
Cemeteries	Polygon	Medium	Low	Low
Flower Beds	Polygon	Low	High	Low
Cycle Paths	LineString	High	Medium	Medium
Monuments	Point	Very High	Low	Medium
Playgrounds	Polygon	High	Medium	High

Organizational

• Data owner: Which department is responsible?
• Update frequency: How often do the data change?
• Quality: How precise must the data be?

Category Schema

Data Model Extension

CREATE TABLE features.category_definitions (
    id SERIAL PRIMARY KEY,
    name VARCHAR(50) UNIQUE NOT NULL,
    geometry_type VARCHAR(20) NOT NULL,
    attribute_schema JSONB NOT NULL,
    osm_tags JSONB,
    wikidata_property VARCHAR(50)
);

-- Example: Cemetery
INSERT INTO features.category_definitions (name, geometry_type, attribute_schema, osm_tags)
VALUES ('cemetery', 'MultiPolygon', 
    '{"name": "string", "address": "string", "opening_hours": "string"}',
    '{"landuse": "cemetery", "religion": "christian"}');

UI Adaptations

• Category selection when creating a feature
• Category-specific forms for attributes
• OSM tag mapping per category

Prioritization

Criteria

1. Administrative relevance: How important is the category for authorities?
2. Community interest: How many users are interested?
3. OSM gap: How incomplete are the OSM data?
4. Technical feasibility: How complex is the implementation?

Prioritization Matrix

High  │ Cycle Paths│ Monuments  │
      │            │            │
Admin.│ Flower Beds│ Cemeteries │
      │            │ (done)     │
      │            │            │
Low   │            │ Toilets    │
      └────────────┴────────────┘
        Low         High
          OSM Gap

Suggest Category

Have an idea for a new category? Create an issue on GitHub!