Sorry to resurrect this thread. Somehow I missed this back in January . Too busy skiing I guess
Samsims has some good points - Navionics does have a refined interface and nearshore maps are pretty much the best of all the off-the-shelf mapping apps out there.
But, TZ iBoats - honestly, its a pretty darn good app. Unfortunately, its only available for Apple products (IOS, iphone, ipad, etc.). So bummer for the Android users.
Its running $19.99 a year for a US map subscription. You get a full trial for 7 days....so if you want to play with it and cancel, they make it pretty easy to cancel if you don't want the subscription.
I tested a full export of waypoints saved from Navionics and also from C-Maps and easily imported them right into TZ iBoat app. They imported in flawlessly.
On import, you lose all the fancy icon symbols and colors...but the name and the coordinate is there - which is the most important thing.
Its really impressive what they crammed into this app and the interfaces is really good and responsive.
First of all, you can choose from between Vector maps, Raster or their BathyVision maps. Below is the BathyVision map that gets much granular contour lines.
What is really slick, is that you can choose the contour line resolution to your liking. Where it says steps (I have it circled) you can get contours down to 5foot.
That is kind of messy on the display...but in some locations, you might want that kind of contour definition. What I like about this is, I can set it to whatever I want or need for a particular location.
I'm sure some of this data is interpolated, but it is still useful and a nice to have.
You can also enable Depth Shading (if you like) and this gives you another perspective of your charts.
For those of us on the North Coast, here is Dinner Reef outside of Garibaldi as a point of reference so you can see what it looks like.
Lots of overlay options:
more overlay options, including weather:
For example, enabling Wind overlay, its an animated display of wave direction and intensity. You can move the slider on the bottom over the time/date to get predictions. The default is GFS model.
wind overlay is the same. Its animated showing intensity and direction of the wind. Again, default is GFS model.
Now what is really cool, is that you can create an event/Point of Interest with pressing on the screen with 2 fingers.
The Fishing Catch Report saves the location, you can add a picture of the fish

, length and weight of fish....its kind of like a log but gets saved on your devices. You can also create other Points of Interest quickly by using the 2 fingers on the screen.
All the data is synchronized between all your devices (phone, tablet, etc.) And you can log into a web browser on their web page and access your data, waypoints, etc from a computer if needed.
The Offline map storage is pretty good too. Its not bulky, so the file size is manageable. The interface is fast and snappy which is because of good coding and compression techniques from a software development perspective.
I do want to share another perspective on things as a software developer. When I export the data from TZ iboats, the GPX file actually has color and symbol provided. Although you might not be able to directly import the 'extra' information, like color into your MFD on your boat...at least the data is there. You could potentially use a tool like GPSBabel to convert it into a format for Garmin (for example).
But when you export Navionics data from the app to a GPX file, it
does not include things like symbol or color. So that kind of stinks. They just give you the Name and the coordinate. So the TZ developers have a more open approach providing you with more not less. I like that.
CMAP export does provide description along with the name and coordinate. But no color, no symbol. So that is kind a a let down.
So for data export...definitely TZ iboats beats them all.
Now regarding weather forecast models....you get GFS. If you want more, you have to pay. For some reason its not an annual sub, but rather a monthly subscription.
So hopefully this helps you out if you are considering using this great tool. There is a lot more features there...I just touched on the big ones.