Geo Metadata & Map Visualization

Overview

OpenRegister will support storing, validating, querying, and visualizing geospatial data via GeoJSON integration, PDOK (Publieke Dienstverlening Op de Kaart) address lookup, and map visualization in the admin interface. This enables location-aware registers for permits, environmental data, social services, and other spatial datasets common in Dutch government use cases.

Status: Planned (spec defined, implementation pending)

Planned Capabilities

GeoJSON Property Type

A new JSON Schema property type format: geojson will be added to support geospatial data:

{
  "properties": {
    "locatie": {
      "type": "object",
      "format": "geojson",
      "title": "Locatie",
      "description": "Geografische locatie van de melding"
    }
  }
}

Supported GeoJSON geometry types: Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, GeometryCollection.

Coordinate Reference Systems

System	Description	Use case
WGS84 (EPSG:4326)	GPS coordinates (lat/lon)	Default; international
RD New (EPSG:28992)	Dutch National Grid	Dutch government data (BAG, BGT, BRO)

Conversion between WGS84 and RD is performed server-side via proj4php.

PDOK Integration

When a schema property is configured with format: geojson, pdokLookup: true, the UI provides:

• Address autocomplete via the PDOK Locatieserver API
• Point placement on a map (Leaflet)
• Reverse geocoding (click on map → fill address fields)

PDOK data sources supported:

Source	Description
BAG (Basisregistratie Adressen en Gebouwen)	Addresses and buildings
BGT (Basisregistratie Grootschalige Topografie)	Large-scale topography
BRO (Basisregistratie Ondergrond)	Subsurface data
Kadaster (BRK)	Land registry parcels

Spatial Querying

Objects with geospatial fields can be queried by location:

GET /api/objects/{register}/{schema}?locatie[within]={"type":"Polygon","coordinates":[...]}
GET /api/objects/{register}/{schema}?locatie[near]={"lat":52.370216,"lon":4.895168,"radius":500}
GET /api/objects/{register}/{schema}?locatie[bbox]=4.8,52.3,5.0,52.5

Spatial queries are executed via PostGIS (PostgreSQL) or equivalent Solr/Elasticsearch spatial plugins.

Map Visualization

The admin UI includes a map view for schemas with geospatial properties:

• Leaflet-based map with PDOK background tiles
• Object locations shown as markers, lines, or polygons
• Cluster markers for large datasets
• Click on a marker to open the object detail panel
• Filter objects by drawing a bounding box on the map

Faceting on Location

Geospatial properties with facetable: true produce geographic facets:

• Grid-based heat map showing object density
• Municipality/province boundary aggregation (via PDOK administrative boundaries)
• Distance-from-point facets (0-1km, 1-5km, 5-25km, >25km)

Schema Configuration Example

{
  "title": "Meldingen openbare ruimte",
  "properties": {
    "titel": { "type": "string" },
    "categorie": { "type": "string", "enum": ["wegdek", "groen", "verlichting"] },
    "locatie": {
      "type": "object",
      "format": "geojson",
      "pdokLookup": true,
      "coordinateSystem": "WGS84",
      "facetable": {
        "type": "geo_grid",
        "title": "Locatie"
      }
    },
    "adres": {
      "type": "object",
      "properties": {
        "straat": { "type": "string" },
        "huisnummer": { "type": "string" },
        "postcode": { "type": "string", "pattern": "^[0-9]{4}[A-Z]{2}$" },
        "stad": { "type": "string" }
      }
    }
  }
}

Standards

Standard	Role
GeoJSON (RFC 7946)	Geospatial data format
WGS84 (EPSG:4326)	GPS coordinate reference system
RD New (EPSG:28992)	Dutch National Grid
PDOK Locatieserver API	Dutch government address/location lookup
PostGIS	Spatial query execution on PostgreSQL

Related Features

• Registers & Schemas — geospatial properties configured on schemas
• Search, Filtering & Faceting — spatial queries and geographic facets
• Object Storage & Lifecycle — GeoJSON stored as object properties