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Displaying Raster Charts in iOS - FAQs

Can the charts be viewed offline?

Yes. The raster charts (and also aerial photos and land maps) can all be used without an internet connection. However, you need to be sure that you view/download the relevant areas on your device to before heading out in your boat.

The app does not have raster charts for my country, but can I still see tacking results?

Yes. The app does include free aerial photos and land maps worldwide. So you can overlay tacking routes on an aerial photo or map where you will be sailing. For example, here is a tacking line going to waypoint, and here is a screenshot showing the distances, times and headings on each tack -- both with aerial photos.

When I zoom in too far, the marine chart disappears. Why do I see the land map?

You are zooming through the detail available on the marine chart. We leave the land maps behind, since they sometimes have additional features that are useful to see. One adjustment that you may want to try is the Overlay Insets toggle in the Marine Charts panel. It lets you display chart insets on top, or underneath for additional detail when zooming in.

Why do some charts pixellate when I zoom in?

Large-scale charts cover large regions and tend to be low-resolution. That's why the government chart offices add more detailed charts and also chart insets in harbors and passages where careful navigation is needed. When printed on paper charts, those insets are usually placed over land areas. The app sets the insets in the correct location on our raster charts so that you can zoom in. On insets where data is available up to the maximum possible zoom level, there may be more detail available on the marine chart than on the land map. So the app keeps the chart on screen in those places, and lets the chart pixellate if you want to zoom further to try to get a larger view of a certain detail on the chart.

When I download in view a chart, does it always stay in in memory, or only for that session?

Usually the charts will stay in cache (temporary RAM memory) for a long time, not just one session. But they can get bumped out at some point, or removed if the app is uninstalled. But don't worry; you can download them again from Marine Charts without any extra cost, and can also download other portions if you didn't get the entire region all at once.

What if an adjoining nautical chart is blocking what I want to see?

"Overlay Insets" is under Options \ Charts \ Marine Charts. It lets you put more detailed charts and insets either on top, or below to zoom in to see their additional detail. Very handy if an adjoining chart is blocking some detail.

Why am I getting the message "Selected chart not in view"?

There are very large data files for certain charts, such as the NOAA chart regions for US waters. To help ensure that you don't unintentionally do a very large, slow download, you can ohly download what is in view. But if you try to download US charts while no relevant areas of the US are in view, you will get this message.

Is there a free version of the SailTimer app in Australia, and marine charts for it?

Yes, there are worldwide Navionics vector charts available in the app on Android and iOS, and also aerial photos and land maps.  But the Australian government is one of the few that does not produce raster charts for digital use.  

Why am I seeing a blue pastel blank screen?

That means that you are zooming in through the nautical chart to the world road maps underneath. The blue pastel is the water color on the road maps. If you zoom in through the marine chart and want to see more detail (or go off the side of the marine chart), it is sometimes useful to still be able to see the worldwide road maps. Just pinch your fingers together on the screen to zoom back out. **Note also that if you have Location Services turned off on your iPhone/iPad, that the app can't tell where you are -- in which case the default view may be centered on the lat/long coordinates 0,0 which are out in the ocean off the coast of Africa.

How are the raster charts in the app different from vector charts?

Raster charts are image files that look the same as paper charts. Vector charts are displayed differently using numerical data, which may allow you to zoom in farther, and which be more suitable for low-resolution GPS screens. Some details and annotations on the print/raster charts may not appear on vector charts. Raster charts like those used in the SailTimer app will pixellate if you zoom in too far. That is why we give you a choice with the Overlay Insets button on the Marine Charts panel, for displaying insets on top, or to zoom down into. It is also why we leave the road maps underneath with more detail, so that you can zoom through the marine chart if you want to see any additional detail that may be available.

Can you use the app and in-app purchases like charts on multiple devices without having to re-buy them?

Yes. When you click the Download button on an additional iOS device, you'll get a message that says "you have already paid for this item, but click here to download it again". If you remove a chart to free up disk space, you can also re-download it later.

To add a new area or missing tiles on the chart, will the "Download in View" or the "Download When Online" buttons get them?

Yes, under Options\Marine Charts\Purchased, you can click "Download in View" for that area, to download it again. That should fill in any missing tiles. This downloads all levels of resolution for the area in view. Try it with a very small area first, since the chart data files are large.

Or for a streaming download as you move the view around, you could turn on "Download When Online" from the Options\Charts panel. Then when you look around, if you have an internet connection (especially a fast one like wifi), any new areas or missing tiles should fill in as you move the view around and zoom in and out. This method only fills in the view at the level of resolution you are currently using, not all levels of resolution.

One other thing you could try is the "Overlay Insets" button on the Options\Marine Charts panel. This either puts the more detailed insets on top, or underneath to zoom down into.

If none of these do the trick, on the Marine Charts panel we put a handy button called "Report Chart Display Problem" to email in a screenshot of exactly what is happening.

Is there a way to use charts from a different app or chartplotter?

We wish there was, but the companies that have licensed charts for chartplotter products in the past now refuse to license their charts for importing into mobile apps. But good news: this means that we have no middleman. So as we get charts directly from each different government, our prices tend to be much lower than traditional paper charts, and than other digital formats such as chart cartridges or downloads.

Will my data still be available if I upgrade the app?

Yes, your waypoints, polars and charts will all transfer to the new version.