A collection of datasets from various Dutch institutions to demonstrate a Spatial Data Infrastructure built on Portolan.
The soil-trench / soil-profile-pit investigation (Dutch wandonderzoek, BRO object SFR — Soil Face Research). A soil scientist exposes a vertical soil face (a pit or trench, typically down to ~6 m) and describes the profile: horizons, texture, colour, organic matter and more. Each record here is one such investigation location (2,806 points), with summary attributes; it is a key field input behind the national Soil Map (Bodemkaart).
Features: 2,806 | CRS: EPSG:4258 | License: CC0 1.0 (public domain) Source: PDOK / BRO (provider VRO). Formats: GeoParquet · PMTiles · GeoPackage (PDOK Atom).
Used in soil science, agriculture, nature-area soil build-up studies, hydrology and land evaluation. Together with soil boreholes (BHR-P) these are the ground-truth observations the Bodemkaart is built from.
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 standardized_location (WKB, EPSG:4258); standardized_location_bbox is a per-feature bounding-box
struct enabling fast spatial pre-filtering.
discipline is always bodemkunde (soil science) for this object.research_report_date and fieldwork_date are free-text date strings, not typed dates.Soil boreholes (BHR-P), the national Soil Map (bodemkaart/soilarea).
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 Soil Trench Investigation (SFR / Wandonderzoek) — Default (https://data.source.coop/cholmes/portolan-nl/vro/wandonderzoek/styles/default.json)styles/by-litter.json — BRO Soil Trench Investigation (SFR / Wandonderzoek) — By litter layer investigated (https://data.source.coop/cholmes/portolan-nl/vro/wandonderzoek/styles/by-litter.json)styles/by-survey-purpose.json — BRO Soil Trench Investigation (SFR / Wandonderzoek) — By survey purpose (https://data.source.coop/cholmes/portolan-nl/vro/wandonderzoek/styles/by-survey-purpose.json)wandonderzoek.pmtilesvia links in
collection.json.Part of the Portolan NL catalog · CC0 1.0 · provider VRO (Ministerie van Volkshuisvesting en Ruimtelijke Ordening).
fieldwork_date |
| string |
| Date of fieldwork (YYYY-MM-DD, free text). |
litter_layer_investigated | string | Whether the litter layer was investigated (ja/nee). |
applied_transformation | string | Whether a coordinate/height transformation was applied (ja/nee). |
standardized_location | binary | Object location — WKB geometry in EPSG:4258 (ETRS89). |
standardized_location_bbox | struct<xmin: float, ymin: float, xmax: float, ymax: float> | Per-feature bounding box struct (xmin,ymin,xmax,ymax) for spatial filtering. |