How to get the directions north/south/east/west with google maps api?

for example I have 5 markers and I want to get the direction (E,W,NE etc) for each one of them according to the main one(red in the center). Here is a pic. Is there a way to do this with google.maps.DirectionsService or calculate it somehow? Thank you.

enter image description here

Upd:Here is what I get: 

m.position.lng() - c.position.lng()
m.position.lat() - c.position.lat()

enter image description here

Answers:

Let me give the idea.
You can use slope. Assume you have a marker M1 and center marker C.
Slope should be equal to (C.lat - C.lng)/(M1.lat - M1.lng)
If the slope happens to be nearly 0 it can be either East or West if M1.lng > C.lng it should be West.
if slope is nearly 1 it is either South West or North East. Then, if M1.lng > C.lng it is South West
If slope is nearly -1 it is either North West or South East. Then i M1.lng > C.lng, it is North West.
You can use the same approach for other directions

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