Verified so far
- Amsterdam says Hudde had measuring stones installed in locks from 1682.
- Measurements established Amsterdam Peil in 1684.
- The Eenhoornsluis Huddesteen survives.
- The inscription says the sea-dike height is nine feet five inches above town datum; the horizontal line therefore sits about 2.67 metres above Amsterdam Peil.
Evidence limits
The groove is not described as NAP zero. This page does not claim that the stone moved, give an unsupported survivor count, or promise current access or condition.
Sources
- 1Amsterdam City ArchivesAmsterdam Peil and the Huddesteen (opens externally)
- 2RijkswaterstaatHistory of NAP (opens externally)
- 3Stichting NAPNAP history (opens externally)