On a recent trip from Port Carmen, Cebu to Port Bonbonon, Negros, in the Philippines, I used an electronic charting program that utilizes BSB chart formats.
My track to the east of Magellan Bay near Cebu City, as shown on the chart (East Coast of Celan, 1:100000), appeared as shown.
The display gave me confidence that this
was good enough for safe navigation.
As my track shifted to another chart (Panay with Negros and Cebu, 1:402000) the display appeared as:
The smaller scale made it more difficult
to correlate the vessel position with the land but still seemed to be accurate
enough for safe navigation.
Later, however, as the wind shifted to 18kts ahead and the current became 1 kt contrary, I discovered that I should have been feeling some bumps on the keel ----- OOPS! :-)