Robot Navigation: Waypoints in Cartesian

Hello to everyone
I have a robot project.
This robot would go to waypoints which are in carthesian. Ex: (3,4) (4,-3) (5,2)
This coordinates will be defined in code.
My teacher said that i should use odometry and compass for this project but when i investigate people use rotary encoder for localization.
My question is can i use rotary encoder with arduino to control my robot in this project?
Is it neccesary to use compass?
Or do you have an idea how to do this project?
My robot will have 3 wheels;
https://goo.gl/images/PSTqeu

How do you plan to use a rotary encoder to tell you what direction you have travelled in?

Steve

Maybe i misunderstood the rotary encoders function. So i cant get the direction and the distance using rotary encoder?

Please do not double post.

So i cant get the direction and the distance using rotary encoder?

A rotary encoder will tell you how much something (presumably a motor or axle) rotated. If there were perfect traction (a pipe dream), you could know how far you have traveled, but not which direction.

This robot would go to waypoints which are in carthesian. Ex: (3,4) (4,-3) (5,2)

3,4 what? Meters? Angstroms? Light years?