The symbols kind of hint at the different informational categories of the map.

the upper left symbol -> tree & deer -> nature -> hint at all the information in the map that related to nature (like forests, rivers, mountains etc.)
the upper right symbol -> three torches -> religion -> hint at all the information in the map that are related to religion (sacred places, monasteries, churches etc.)
the lower left symbol -> crown -> politics/reign -> hint at all political information in the map (political borders, capitals, castles)
the lower right symbol -> wheel -> trade/merchants -> hint at all information in the map that are related to trade (routes, streets, citys (with markets), ports etc.)

don't blame your german ... it's pretty good.