[GPSNavX]

No intent to disregard the question, I just wanted to see if I could reproduce what you reported. I found the "+" and "-" buttons on the Chart view worked as intended.

The "+" button will present a list of all the larger scale charts that intersects with the center of the Chart View. They are sorted largest scale to smallest scale. So to get the best detail, select the first chart in the list.

The "-" button will present a list of all smaller scale charts that intersects with the center of the Chart view. They are sorted largest scale to smallest scale. So to get the least detail pick the last chart in the list.

In Just about every area NOAA RNCs cover there are multiple scales of charts available and multiple overlaps. Charts rarely exactly border each other, but instead overlap.

One possible option would be to plot the chart borders. This might assist in seeing if there are charts overlapping, but it also might just clutter on the small iPhone screen.

iNavX will automatically switch from chart to chart as the GPS position changes if "Pos. Icon Kept Visible" is On in the Chart Setup.

If you have a suggestion for a better or another method for switching to another chart please provide it.