The LH3 UI includes the two finger gesture pinch-to-zoom which is familiar to most cell phone users. It has an annoying side effect: once zoomed, the display is taken out of the moving map mode and into the fixed map moving boat mode. The zooming action also causes a display mode change.
I have other moving map applications on a number of vehicles, boats, and aircraft. In my opinion a far better UI is to return to a moving map mode after the scale change, unless there is also a large pan move. In other words, if I pinch to zoom but keep my fingers in roughly the same location on the screen, it performs a zoom but no movement mode change. In the case of the chart app, I would do this with a dead band around the My Boat icon.
So for example: to zoom in, I pinch to zoom near the boat icon, display zooms but leaves the display in moving map mode and the boat centered (or offset depending on settings). The assumption is that I just want a chart scale change, and nothing more. If instead I pinch to zoom in a location away from the boat, the assumption would be I am interested in that specific location, it could shift to fixed map mode and center the zoom on the location of the pinch initiation. This is how the friendlier map applications work. On the Axiom, I fear I will wear out the location on the screen which is the return to boat centered icon, as I have to hit it so often.
Along with this, keep the chart in moving map mode when I touch (but do not drag) anywhere else. The UI requires a short or long touch in many instances, to get a range, to access an AIS target, etc. You do that a lot in LH3. Each time I do, it takes the chart app out of moving map mode. Each time I have to hit the return to center icon. The glass is getting thin there :). If I want a pan, I'll drag. Again a small dead band, because in lumpy seas you are going to be moving your finger a little like it or not.
The final refinement would be to remember the zoom level when I hit the return to center icon. For example, I touch and drag to see a different area on the chart. This automatically reveals the return to center icon. I then pinch to zoom (or +/-) to further see what I am interested in, place a waypoint, etc. When I touch the return to center icon I am returned to the boat's location, AND the zoom as it was before. I am done with what I was looking at, just want to go back. This is much more in keeping with how the chart application is used. It separates zooming and panning from display travel modes which are now confused.
I'd be happy to talk to someone about this and demonstrate (on another application) how well it works.
