Electronic navigational charts (ENC) are not at all new to navigation. They have been in use by commercial vessels for over 20 years, but they have not really caught on much with recreational mariners. This is in part because they look different from paper charts, but also largely because their presentation on the screen and how users interact with them is so different from the use of raster navigational charts (RNC), which are static images of the paper charts.
One of the things that is notably different with ENC is when you zoom out on the chart, the chart symbols and text labels do not change size. They can do this because ENC are all vector products and they just redraw everything at each new scale, and this keeps the symbols and text in view
That is, unless you happen to be zooming out on a region that has a lot of symbols. Zoomed in they are far apart on the screen but zoomed out they pile up to the point of becoming totally unreadable.
Charts in the top two groups have overlapping coverage of at least one of the objects listed; the bottom group are adjacent and overlapping charts.