A collection of datasets from various Dutch institutions to demonstrate a Spatial Data Infrastructure built on Portolan.
Map-area collections of the national Geomorphological Map 1:50,000 (BRO object GMM) — 70 polygons that group the map by survey / publication unit.
Features: 70 | CRS: EPSG:28992 | License: CC0 1.0 (public domain) Source: PDOK / BRO (provider VRO). Formats: GeoParquet · PMTiles · GeoPackage (PDOK Atom).
Use to understand provenance/version groupings of the geomorphological map.
This collection comes from the Basisregistratie Ondergrond (BRO) — the Dutch Key Registry of the Subsurface, a statutory base registry in force since 1 January 2018. Government bodies must register subsurface data in the BRO and may only use registered data for public tasks. Data is published openly via PDOK, usually within ~1 day of registration. The Ministry of Housing and Spatial Planning (VRO) is the system-responsible provider; the data here is produced by TNO – Geologische Dienst Nederland (subsurface objects) or Wageningen Environmental Research (the soil and geomorphological maps).
Two BRO concepts appear in almost every dataset:
bro_id — the unique registration identifier of each object (e.g. GMW000000012345).quality_regime — IMBRO (full quality assurance) or IMBRO/A (transitional data delivered under a lighter regime; treat with slightly more caution).DuckDB (analytics):
GeoPandas:
Geometry is stored in geom (WKB, EPSG:28992); geom_bbox is a per-feature bounding-box
struct enabling fast spatial pre-filtering.
geomorphological_area (the map).
Column names in this collection are the English BRO field names. Common Dutch equivalents:
bronhouder = delivery_accountable_party (data owner), kwaliteitsregime = quality_regime, bodemklasse = soil class, hoofdklasse = main soil class, genese = genesis (landform origin), reliëf = relief, boring/booronderzoek = borehole, sondering = cone penetration test, grondwater = groundwater, mijnbouw = mining, bodemverontreiniging = soil contamination.
Mapbox GL v8 style files (use with MapLibre GL JS, OpenLayers via ol-mapbox-style, or any Mapbox GL v8 renderer) live alongside the PMTiles:
styles/default.json — BRO Geomorphological Map — Map area collections — Default (https://data.source.coop/cholmes/portolan-nl/vro/geomorfologische_kaart/geomorphological_area_collection/styles/default.json)styles/by-method.json — BRO Geomorphological Map — Map area collections — By inventory method (https://data.source.coop/cholmes/portolan-nl/vro/geomorfologische_kaart/geomorphological_area_collection/styles/by-method.json)geomorphological_area_collection.pmtilesvia links in
collection.json.Part of the Portolan NL catalog · CC0 1.0 · provider VRO (Ministerie van Volkshuisvesting en Ruimtelijke Ordening).
geom_bbox| struct<xmin: float, ymin: float, xmax: float, ymax: float> |
| Per-feature bounding box struct for spatial filtering. |