How to view current-atlas pages and build multi-page PDFs for a trip — including a single PDF that shows several subregions at the same time.
The tidal current maps are generated by Richard Dewey in his Salish Sea Tidal Currents Volumes 1–4, freely available at www.dewey.ca. The tidal current maps are based on the tidal model of Foreman et al. (2004). David Leaf, dsleaf@gmail.com, produced the web application that stamps time and date, island names, and CHS and NOAA current-station predictions.
Each app shows the Salish Sea Tidal Current Atlas for one region. You pick a date and hour, and it shows the atlas page for that moment — the arrows on the page show current direction and strength. Every map can be stamped with the exact date/time and live current-station predictions, then exported as a JPEG or PDF you can carry offline on a phone or tablet.
| App | Region | Subregions |
|---|---|---|
| SJI | San Juan Islands (Vol. 1) | A–H |
| DB | Discovery & Broughton Islands | A–H |
| NGS | Northern Georgia Strait | A–H |
| PS | Puget Sound (Vol. 2) | A–F |
The subregion letters are the tabs across the top of the app. Tap 🗺 … Subregions to see a map of which letter covers which area.
Zoom with the − / + buttons. The stamp you see on screen is exactly what gets burned into your exported files.
The ⚙ Build & Export button is how you generate a multi-page document in one step. Click it to open the panel, then fill in:
| Field | What it does |
|---|---|
| Start / End Date | The day range to cover. Use the same date in both for a single day. |
| Start / End Time | The hours of each day to include (e.g. 07:00 to 19:00 for daylight). |
| Subregions | Comma-separated letters, e.g. A,B,C. The order you type them is the order they appear in the PDF. |
| Page Order | Time-major or Sub-major — see section 4. |
| Split PDF / N days | Break a long trip into one PDF per N days. Leave blank for a single PDF. |
| Phone PDF | Also build a smaller, phone-sized version of the PDF. |
As you type, the estimate (e.g. ≈ 48 maps · 2 days · 1 PDF) updates so you know the size before building. Click Build & Export, wait for it to finish, then click the download links that appear (one JPEG ZIP plus one PDF, and a phone PDF if you ticked it). If a split produces several PDFs, a ⬇⬇ All PDFs button downloads them all at once.
This is the key choice for trip planning. The Page Order setting decides how the pages are interleaved.
For each hour, it places every subregion you listed back-to-back. Flip through the PDF one hour at a time and see the whole route's currents together.
For each subregion, it places every hour in a block. Good when you want all of one area's pages together.
You're paddling through three subregions on July 18 and want one PDF where each hour shows all three areas side by side as you flip pages.
2026-07-18 (same day in both).07:00, End Time 18:00.A,B,C (in the order you'll travel them).The result: A 7am, B 7am, C 7am, A 8am, B 8am, C 8am … — at every hour you see all three subregions together.
You want each subregion's pages grouped together so you can follow how that one area's current builds and slackens through the morning.
2026-07-18 (same day in both).08:00, End Time 11:00.A,B.The result: A 8am, A 9am, A 10am, A 11am, B 8am, B 9am … — each area's hours stay together, so you can see how the current in that one subregion changes over the morning.
Build & Export covers whole date/time blocks. But when your trip threads through several subregions at different times — you're in area A at 8 am, cross into area B by 9 am, reach area C by 10 am — you can pick exactly those maps by hand and export just them, in the order you'll travel.
Use Prev / Next to step through your selected maps on screen, All to select every hour shown for the current subregion, and Clear to start over.