I'm doing a project on geometric hashing. Of which i am unsure about the basis generation (meaning, finding only a pair coordinates that coincide with the X-axis) from all the invariant points in the coordinate file of a given 2D model which would have been hashed already. This case being, we could also orientate the model in space further, so that all 2D models in the database can be automatically go through an appropriate offset.

Your help is greatly appreciated.