Old maps give clues which show how places change over the years. Some maps were drawn so that a landowner knew where the edge of their land was. Others were drawn so that the army and navy knew how to defend Britain against invasion…hence “Ordnance” Survey.  
Looking at maps is a good way of seeing the pattern of streets. Can you find any other patterns by looking at maps? About 200 years ago long straight roads were put into Aberdeen. Can you find them in the map?  
Discover old maps of Aberdeen and other places in Scotland on-line at the National Library of Scotland. Historic Scotland’s “Pastmap” has maps with important historic buildings and monuments marked on.