How to Download (and Update) offline charts in Navionics in Preparation for a Passage
This video will demonstrate how I ensure I have necessary offline charts before a passage. The process itself is applicable to any chartplotter app.
Script for this video:
This video will demonstrate how I ensure I have necessary offline charts before a passage. I’m going to go through this process in Navionics because, one, I use it and, two, it’s the most popular smartphone chartplotting app. The process itself is applicable to any chartplotter app.
For demonstration we’ll use a passage from Portland, ME to the Cape May Harbor, NJ
You swipe and pinch to move about the globe in Navionics, similar to any other map app
Notice how Navionics downloads the charts after we zoom in to Portland. When connected to the internet Navionics will download charts that you’re subscribed to on demand as you pinch and drag around
You can observe the same thing at Cape May Harbor
Notice Navionics lightens the areas where detailed charts are downloaded
Once I know the route of a passage the process is as follows:
- WiFi Internet (recommended)
- Verify Subscriptions
- Download Charts
- Update Charts
- Disconnect Internet
- Verify Charts
Let’s jump into this process.
Now you don’t really need to be on Wifi. In a pinch I’ve definitely used cellular data to download charts I needed. I also regularly have chart updates that exceed a gigabyte so whenever possible I use wifi for Navionics chart downloads!
Next you must verify the chart subscriptions you need are current. You can see I have a few expired chart regions but the one we need for this passage, US and Canada, is current. If you haven’t previously purchased charts you’ll have to go to ‘add region’ and select USA or US and Canada and click on the price to purchase the region.
If you don’t plan on sailing in the US you should follow along in a region where you’ve purchased a subscription.
Next up you is the most obvious step: you download the charts. Open the menu and select “Download Maps”
Navionics then prompts you to download charts one rectangular region at a time.
As you zoom out you’ll find that Navionics limits the amount of charts you can download at one time by limiting the size of the rectangle.
Place the rectangle over some or all of the charts you need an click download to store the charts locally.
I err on the side of downloading more than I think I’ll need
Again note Navionics lightens the map in areas where charts have been downloaded
Once I’ve downloaded the new charts I force Navionics to update charts downloaded previously
This one is simple – just click “Menu > Update Maps“
if your CURRENTLY SUBSCRIBED charts are up to date Navionics gives you this prompt.
Otherwise you click “Update” to download updated charts.
Now it’s time to check our work
Disconnect the app from the internet. Here I just disable wifi and I can see that my phone is in airplane mode and offline.
Zooming in to a dark, not yet downloaded area confirms that navionics is no longer connected to the internet and shows you what it looks like when detailed charts are not available.
Scrolling north you can see the border where my download ended. South of the rectangle selected Navionics has no detailed data to render charts; further north we have detailed charts and you can see watch as Navionics renders them.
I spot check our destination, Cape May Harbor. Then I check an area that wasn’t downloaded in our initial route scouting: Nantucket island. Everything looks good. Lastly I verify charts for Portland.
At this point I’m satisfied that I have downloaded up to date charts for the passage from Portland to Cape May Harbor. Still, if this were a real passage I would do the remainder of my passage planning disconnected from the internet so that I would discover and download any missing charts.
Caveat: Expired Subscriptions
Earlier I showed you subscriptions that had expired months ago. I also showed that the “Update Maps” feature indicated all of my charts are up to date.
If I navigate to waters covered by the expired subscription and select a rectangle of charts for Navionics to download it will correctly indicate that I need to purchase a subscription to get the charts I need. In this case it’s a renewal – if I hadn’t previously subscribed Navionics would prompt me to purchase a subscription.
ALWAYS make sure the subscriptions you need are up to date!
Sonar Charts and Government Charts
Navionics can have three different chart sources for a given area. The Native, Navionics chart is what we’ve used up until now.
Then there is the Sonar Chart made up of crowdsourced depth sounder data in well trafficked areas. This is usually far more detailed than Navionics charts.
In some regions there are Government charts. These are often at least one of the sources for the Navionics charts and have the advantage of being free.
You’ll notice that my phone has been disconnected from the internet while I’ve been showing you these other chart sources; our initial download actually downloaded all three sources of chart data even though we were set to Navionics mode while performing the download!
Navionics charts are, of course, the preferred chart source to use. The government charts are displayed quirkily enough in Navionics that I wouldn’t use them for primary navigation. The Sonar Charts are much more detailed but not from an authoritative source and not usable at the scale necessary for passages. Still the additional information is good to have at least as a reference.
The buttons you press and the method for selecting which charts to download are different using other apps. Still, I follow the same process for verifying offline charts for each app I use for navigation.
I’m thinking of keeping a series of Navionics videos going on Youtube and if I do be sure to I’ll link the here. If you’d like more videos covering Navionics let me know in the comments, especially if you’d like specific topics covered, or just hit this video with a like.
Thanks for watching and I’ll see you out there!
Concern : shallow water indicated – where do I find exact depth ? And is depth ft. or meters ?