This is a simple heat map that shows a player's individual corsi when they are on the ice against a specific player from the other team. For instance, you will see when David Backes was on the ice against Henrik Sedin, he had a -4 corsi. Whereas, when Roman Polak was on the ice against Kevin Bieksa, the he has a +9 corsi.
What does this mean? It means, when Backes was on the ice at the same time as Henrik Sedin, the Canucks had 4 more shots (blocks, misses, saves, and goals) than the Blues did. And when Polak was on the ice against Bieksa, the Blues had 9 more shots than the Canucks did. Of course it only includes the shot events that occurred at even strength. And keep in mind, just because there is a missing value, that doesn't mean the two players didn't see time on the ice against one another. It just means that no shots took place.
This isn't a very sophisticated analysis, and I doubt you can draw too much from it. This was actually a by-product of another project I am currently working on, but I spent so much time on it, I had to do something with it. So I thought I would post it here.