Sources and licenses

This directory is assembled from open data.

Tides — measured, and modeled

In United States waters the tide window and timing is computed from data published by the Center for Operational Oceanographic Products and Services, part of the US National Oceanic and Atmospheric Administration, whose work is in the public domain.

In Canadian waters the high and low waters are retrieved from the Canadian Hydrographic Service. This page contains information licensed under the Open Government Licence – Canada. Where we cannot show data from CHS for Canadian waters the page falls back to the global model below.

Outside the US and Canada the tide data is interpolated from FES2022, a global tide model built from satellite altimetry: The FES2022 Tide product was funded by CNES, produced by LEGOS, NOVELTIS and CLS and made freely available by AVISO.

In the mobile app, rock pools in the UK and New Zealand are computed from the UK Hydrographic Office and NIWA, respectively.

All of these are astronomical predictions, not forecasts — they do not know about weather. Never plan a crossing or a climb-out from the information on these pages.

Species records — iNaturalist

The species listed on rock pool locations come from iNaturalist observers: the identifications, how often each was recorded, and the months it was seen in.

Place names and coastlines — OpenStreetMap

Some place names on this site were looked up from OpenStreetMap. Those names are © OpenStreetMap contributors, available under the Open Database License.

The coastline drawn on each card, and the nearest car park named on a rock pool page, are OpenStreetMap data under the same license.