We have more standardized maps now, we are so used to mercator projections, that we forgot the old standards. (eg road maps not true to the north, with true distances for roads only.)
Speaking of Mercator, the book was printed 4 years after his death.
Europe was also fairly well known, omissions are likely not due to lack of knowledge but rather lack of significance to their customers (dutch traders?).
They als seem to have moved places further appart, if their representation would merge on the maps. (Spandau to Potsdam 15 km)
[btw Hannover is missing, Braunschweig is there :-), the duke of braunschweig moved to Hannover 50 years after the map was published.]
In the germania map they have used different scales for different areas.