The Cultural Heritage Agency lists 63,073 rijksmonumenten across the Netherlands — protected by law, frozen in stone. 881 of them sit inside national park boundaries. Joining each monument's point location to the BAG building footprint it falls within — when there is one — pulls 578 footprints out of the cadastre and lets us see which monuments are actually buildings, how old, how big, and what survives.
The monument register stores a point for each protected site. The cadastre stores a polygon for each building. Drop the monument point inside the right polygon and you have its footprint — its real shape, its real area, its real age (from bouwjaar). For 578 of the 881 monuments inside parks, this works cleanly. For 303 it doesn't — and the failures are revealing.
For monuments whose location was originally placed using a BAG building (515 of 525), the spatial join is essentially perfect. The point sits inside the building it was sampled from.
None of the 73 archaeological monuments fall inside a BAG building — exactly as expected. They are buried sites, prehistoric mounds, ruins, fossil landscape features. There is no roof to put over them.
Garden features, statues, ornamental gates, hydraulic works — protected, but standing in fields rather than buildings. Herkomst BRK / divers shows the lowest match rates: these are land parcels and "miscellaneous", not structures.
Across the Netherlands the rijksmonumenten register is dominated by ordinary urban heritage: Woningen (residences) make up half the country's protected stock. Inside national parks, that pattern flips. The leading category is Kastelen, landhuizen en parken — castles and country estates — followed by boerderijen en molens (farms and mills). This is not coincidence: many parks were created around historic estates, sometimes from a single bequest. The country house is often the seed of the conservation area.
| Category | In parks | Nationwide rank | Over-represented? |
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The matched footprints carry bouwjaar — original construction year — and the spread is striking. Buildings dating to the early 1200s still stand in Drentsche Aa and Van Gogh: parish churches at the heart of medieval villages, and at least one boerderij (farmstead) recorded as 1261. The mid-19th to early-20th century is the densest era — country house construction during industrialisation, and rural reconstruction after WWII.
When the BAG join lands on a monument, we get the full footprint — and then we can sort by it. The largest matched monument-building in any Dutch national park is a 10,859 m² complex from 1937 in De Hoge Veluwe: the Kröller-Müller Museum and surrounding pavilions. The next group are 19th-century cloisters and seminaries in Van Gogh National Park.
Some of these dates are reasonable estimates rather than precise — medieval bouwjaar values are often the start year of the oldest surviving fabric — but the picture they sketch is right. Romanesque and early-Gothic parish churches in Drentsche Aa, and a remarkable cluster of structures dated 1303 in Van Gogh, all in a single kasteel complex.
Park polygons stream live from nationale_parken.pmtiles. The faded grey buildings underneath stream live from bag-light.pmtiles — all 11.4M of them, fetched only as you zoom. The coloured polygons on top are the 578 monument footprints we recovered through the spatial join, painted by category. The little circles are monument points — solid for exact location, ringed for globaal (approximate within 10–100m). Use the filters to focus, or pick a park to fly to.
| # | Park | Hectares | Monuments | Per 1000 ha |
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