Slope diagram
The SLOPE plate computes the steepness of the ground from the AHN4 ground model and divides it into 6 bands chosen for flat country.
Updated 15 October 2026This page was written by AI.
Overview
Most of the Netherlands is flat at the scale of this plate. With the bands used in the other editions (5, 10, 15, 20°) a Dutch plate is almost empty. The Netherlands edition therefore uses finer bands, so that dykes, canal banks, raised roads, embankments and dunes show up.
Bands
| Band | Meaning |
|---|---|
| Under 0.5° | Flat (most of the ground) |
| 0.5–1° | Barely perceptible fall |
| 1–2° | Gentle fall, for example along raised streets |
| 2–3° | Noticeable slope |
| 3–5° | Slopes of dykes, quays and embankments after smoothing |
| 5° or more | Steep for the Netherlands (dunes, dyke faces, Limburg) |
In percent, 0.5° ≈ 0.9%, 1° ≈ 1.7%, 2° ≈ 3.5%, 3° ≈ 5.2% and 5° ≈ 8.7%.
Share of ground at 0.5° or more within 800 m: TU Delft BK City 17.6%, Amsterdam (Academie van Bouwkunst) 37.4%, Rotterdam (Academie van Bouwkunst) 50.7%.
Method
| Item | Content |
|---|---|
| Elevation data | AHN4 ground model (DTM, 0.5 m), averaged to 5 m, gaps under buildings interpolated; Copernicus DEM GLO-30 only over wide water |
| Slope | Derivative of the east–west and north–south height differences at each grid point |
| Smoothing | 25 m in the Netherlands (50 m in the other editions) |
| Bands | 0.5 · 1 · 2 · 3 · 5° (6 bands) |
The note on the plate states the bands, the maximum and mean slope and the smoothing width.
Limitations
- Features narrower than about 25 m (a ditch bank, a ramp) are flattened by the smoothing
- The ground model has buildings removed; bridges and viaducts can remain as short steep strips
- AHN4 was surveyed 2020–2022. Later earthworks are not included
- The plate reads landform at concept stage. Levels for design and drainage need a survey
Data sources
- AHN4 (Actueel Hoogtebestand Nederland), CC0 · where water is wide: Copernicus DEM GLO-30 (© DLR e.V., © Airbus Defence and Space · ESA)
Related guides
© sitedia · Home · About · All guides · Pricing ·
Terms · Privacy · Contact · Data sources ·
Other editions: Korea · United States · Japan · Spain · United Kingdom
Example plates: BAG (Kadaster, CC0) · © 3DBAG by tudelft3d and 3DGI (CC BY 4.0) · BGT, NWB, AHN4 (CC0) · Kadaster, Beeldmateriaal.nl, PDOK (CC BY 4.0) · © OpenStreetMap contributors (ODbL)
Example plates: BAG (Kadaster, CC0) · © 3DBAG by tudelft3d and 3DGI (CC BY 4.0) · BGT, NWB, AHN4 (CC0) · Kadaster, Beeldmateriaal.nl, PDOK (CC BY 4.0) · © OpenStreetMap contributors (ODbL)