BRO Geomorphological Map 1:50,000 — Geomorphological areas (GMM)
What this is
The Geomorphological Map of the Netherlands 1:50,000 (Dutch Geomorfologische kaart, BRO
object GMM), produced by Wageningen Environmental Research. Each of the 80,148 polygons is a
landform, classified by genesis (how it formed — eolian, fluvial, marine, glacial,
periglacial, anthropogenic, …), relief form, and landform subgroup. The classification is
denormalised directly into the feature, so it is ready to map and analyse.
Used in landscape ecology, archaeology (landform predicts site potential), nature development,
water management and spatial planning.
About the BRO
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).
How to access
DuckDB (analytics):
GeoPandas:
Schema — field meanings
Column
Type
Meaning
fid
int64
Feature ID.
collection_id
string
identification
string
relief_code
int64
Relief-form code.
active_process
string
Whether the landform process is still active (ja/nee).