Tideline - tide widget

We often go on vacation near the coast, and it was annoying to look up the tide forecast.

Tideline calculates astronomical tides offline using bundled EOT20 ocean data, and shows a forecast using a simple Android widget. As it is an offline forecast with limited information and no weather forecast it is not precise, with a median error of around 6% in testing. It is most useful for deciding when to go for a walk along the beach.

The widget shows a tide curve around a central mean-sea-level line, the next 24-hour high/low range and the predicted height in centimetres at the last update. Tap for a full-day graph, next high and low times, and settings.

Choose a fixed coastal location or approximate current location. Optional background following accesses approximate location while the app is closed to keep your widget near you as you move. It is off by default and requires your permission. Only the latest fix stays on your device; TideLine does not upload location or keep a travel history.

Choose a 2, 3, 4, 6, 12 or 24-hour view, starting with four hours. Read whole-hour labels above and below the axis, with quarter-hour and half-hour ticks in the shorter views. Adjust colours, transparency, label size, line thickness and padding. Each widget has its own settings.

Widget refreshes are approximately every 15 minutes and may be delayed by Android. Location following also updates occasionally. The bottom-left timestamp identifies the last calculation; the widget is not a live clock.

No accounts, advertising, analytics or live forecast requests. Tideline has no Internet permission.

Tides are approximate astronomical predictions. At tested coastal sites, median RMS error was 5.3% of tidal range (6.5 cm); this sample does not represent all coasts, and local errors can be much larger. Weather effects such as wind and storm surge are excluded. Some coastal locations are unsupported, including the Caspian Sea. Heights are relative to model mean sea level, not chart-datum depths. Do not use TideLine for navigation, safety decisions or critical activities.

Data: EOT20 by Hart-Davis and colleagues, CC BY 4.0, with lossless coastal conversion. Shoreline: Natural Earth, public domain. Astronomical reference: pyTMD, MIT. Full data and software notices and the privacy policy are included in the app.

More apps by this developer: https://play.google.com/store/apps/dev?id=6256987868491351341