What conclusions can be drawn from the image in the link below?http://www.brown.edu/Departments/Italian_Studies/dweb/images/maps/decworld/plaguetraderoutes.jpg
There are a number of conclusions that can be drawn from this map.
First of all, you can conclude that trade caused the spread of the Black Death. This can be seen from the fact that the plague started in China and then spread to parts of Europe that had trading connections with China.
Second, you can conclude that trade by sea was faster than trade by land. We can see this in the fact that the Black Death reached areas like England (that were accessed in part by water) more quickly than it reached Muscovy (which was accessed only by land).
Finally, we can conclude that Spain and Portugal were not yet important trading nations at this point in their histories. We can see that no major trade routes reached those countries.