A collection of datasets from various Dutch institutions to demonstrate a Spatial Data Infrastructure built on Portolan.
Open aerial imagery from Beeldmateriaal Nederland, the Dutch national collaboration for aerial photography. Since 2011, this partnership of municipalities, provinces, water boards (waterschappen), Rijkswaterstaat, Het Kadaster, and other government agencies has jointly commissioned nationwide aerial surveys, sharing costs and ensuring uniform quality.
Two campaigns fly each year:
The resulting orthophoto mosaics cover the entire Netherlands and are published as open data under CC BY 4.0. Coordinated under the Geo-Informatieberaad (GI-beraad), the programme also produces the Actueel Hoogtebestand Nederland (AHN) LiDAR elevation dataset. From 2023, coverage extends to the Caribbean Netherlands (Bonaire, Sint Eustatius, and Saba).
Headquartered in Amersfoort — the origin of the Dutch national coordinate system (EPSG:28992).
Website: https://www.beeldmateriaal.nl/ Open data portal: https://opendata.beeldmateriaal.nl/ License: CC BY 4.0
12 tiles from the 2024 summer campaign covering ~450 km² around Amersfoort at 25 cm GSD. Each tile covers one kaartblad (Dutch map sheet, ~5 × 6.25 km) on the Amersfoort / RD New grid (EPSG:28992).
Two assets per tile:
All files are Cloud-Optimized GeoTIFFs with JPEG compression, 512×512 internal tiling, 6 overview levels, and baked-in per-band statistics.
See luchtfoto_2024/AGENTS.md for detailed band descriptions, code examples, interactive
map recipes, and cross-dataset analysis patterns.
Base URL: https://data.source.coop/cholmes/portolan-nl/beeldmateriaal/luchtfoto_2024/
Quick start:
The published products are orthophoto mosaics — stitched from the central portions of individual aerial photographs to minimize building lean and perspective distortion. Two types are produced each year:
Shortly after each campaign, a "quick" variant is released — usable for orientation but not yet meeting all geometric and radiometric quality requirements. The definitive product replaces it after the full quality control process.
The winter CIR capture provides near-infrared reflectance data useful for vegetation analysis. In this catalog, CIR band 1 (NIR) is combined with summer RGB to create 4-band RGBNIR COGs. Note that RGB and NIR are from different seasons.
Tiles follow the Dutch national kaartblad grid. Each sheet is identified by a number (e.g., 32) and a combination of letters indicating the block and position (e.g., DN1). The full tile code (e.g., 32DN1) locates a specific ~5 × 6.25 km area.
Other collections in this Portolan catalog pair well with the orthophotos:
ee.ImageCollection("Netherlands/Beeldmateriaal/LUCHTFOTO_RGB")Hand-maintained agent guide (ported from this collection's llms.txt in August 2026). Update it alongside collection.json.