Reading the blanks on maps, what isn’t there or has been omitted (two very different things) is as important as interpreting what is on the map. But why should there be any blank spaces at all? Here are three very different answers, from three very different maps.
It’s blank because they can’t/won’t let you map it
Richard Horwood’s map of London was the largest map ever printed in the British Isles when it was published in the 1790s. He was the first to show individual house numbers on a map of the capital, but was refused permission to survey the interior layout of the Tower of London – then a functioning military installation. In the 20th century the Ordnance Survey deliberately omitted airfields, military bases and even the Post Office Tower from its maps, and in the 21st Googlemaps makes judicious use of pixelation.
It’s blank because we don’t know what’s there
‘So geographers, in Africk maps, With savage pictures fill their gaps, And o’er unhabitable downs Place elephants for want of towns’. Swift was satirising bad poetry rather than talking literally about poor standards of mapping, but his analogy worked for 18th century readers because it struck a chord. The decorative elements on maps are rarely there by chance – their significance is a subject in itself – but they are often deployed where knowledge was sketchy. These elephants are frolicking on a map of Africa which was first published by Janssonius in the 1630s, and was still being published without any cartographic revisions by Schenk and Valk over 70 years later.
It’s blank because there’s nothing there
On the SDUK map of Venice, engraved in 1838, the eastern tip of La Giudecca is completely blank, even though neighbouring buildings and formal gardens are shown in considerable detail. It wasn’t a military installation this time – the arsenal is shown with glorious precision – so we are invited to assume that there was nothing there worth mapping. I’ve seen maps of Venice from 1807 and 1850 which show gardens, but given the attention to detail shown by the SDUK I’m inclined to believe that the earlier cartographer was making an educated guess. Send us a postcard if you know better!