Day vs. Night population maps | IELTS, ESP, EAP and CALL | Scoop.it
From www.joelertola.com - October 12, 2012 3:31 AM

A great image for showing the pulsating rythmns of a dynamic urban system.  We treat population density as a static metric, but how many people are in a given place would truly be difficult to fully quantify.  What logisitic difficulties would this shift present for cities?